Ingersoll-Rand 10" x 12" 300 HP Diesel Engine

Most historians and railfans are aware that the first commercially successful diesel-electric locomotives to be produced in the United States incorporated a diesel engine manufactured by Ingersoll-Rand, but have never seen that engine. Let's take a brief look at this design and how it was built.

For this article, we're using an Ingersoll-Rand maintenance manual for the photos and data, courtesy the David A. Davis collection. We think it may have been printed about 1935. At left is an overall view of the engine, which had the following characteristics: 10 inch bore and 12 inch stroke; idle speed 250-275 RPM depending upon auxiliary load; full speed 550 RPM at full load, and with light load full speed was 570-575 RPM. The engine was rated at 300 brake horsepower.

This diesel engine was developed by Ingersoll-Rand for use in locomotives - but in fact this diesel engine really bears no resemblance in any way to common diesel engines for locomotive service that appeared later. For example, the use of exposed push rods was common at the time (even in submarine diesels) and so it was carried over here; no doubt, the problems of dirt and dust in locomotive service weren't yet well appreciated. Note also the use of totally exposed cylinder units; these were a common thing in early, large gasoline, distillate and oil (otherwise known as Diesel) engines at the time as well but later engines of all builders enclosed the cylinders fully in the engine frame. (Item: The first to get back away from this was the Cooper-Bessemer FWL and later FDL series.)

The manual covers two models of engine, known as the 360C and 420C models. These differ mechanically in compression ratio; the model numbers used are actually references to the peak compression pressures for each model. Valve timing and injection timing also differ between the two models. The modest power output of these engines, given their displacement and speed, is more understandable when one reads tha the peak firing pressure of these engines was on the order of 500 to 550 pounds - so that for the 420C the firing pressure at the maximum limit was only 130 pounds higher than the compression pressure. One other change between models was minor- the location of the fuel transfer pump.

Let's take a look at a section drawing of the engine to begin to see some construction features.

This drawing was originally intended to show oil flow - which with the red lines we can see flows through the drilled crankshaft to the connecting rods and then to the pistons, finally draining from their undersides into the sump - but really shows other details quite well. Note at the right the large flange used to mount the main generator, and the flexible coupling inside of that. These engine-generator sets used spring loaded bolts to hold the sets to the I-beams in the center of the locomotives, helping ensure that road shock and frame flex were not transmitted to the set (and thus the crankshaft.) Note also the pent-roof pistons, commonly seen with the Price fuel injection system concept which we'll examine in a moment. Some cylinder head details are visible here; note the long studs going from the top of the heads all the way down into the cylinders. Note also that the heads make positive full contact between each other; the heads not only contain (enclose) passages that connect to one another forming intake and exhaust manifolds (with appropriate pipe connections at the ends of the engine) but also form an upper longitudinal strength member for the engine.

Here's a closer look at the cylinder head - and if we look closely we see that the head is actually mounted on top of a piece that is interposed between it and the cylinder unit. This piece is called the combustion chamber; thus, the head itself contains only the valves, rockers, injection nozzles and so forth and is mounted on top of a separate cylindrical but short piece that forms the combustion volume when the piston is at TDC. The two fuel injector nozzles pointing into the combustion chamber at 180 degrees from each other are typical of the Price injection system design. The small valve is for air starting the engine.

Here is the engine base, turned upside down. This is the main strength member of the engine; it mounts the main bearings and thus the crankshaft as well as the camshaft. The cam deck is visible on the bottom (remember that this view is upside down as in the manual) with holes for the push rods to pass through. The housing mounts on top of a base, which serves only to collect lube oil acting as a sump, and of course as a support.



At left, one of the cylinder units. Six studs are visible which are used to attach the cylinder head (with interposed combustion chamber.) Note the flange around the base of this unit, used to bolt it to the engine housing we just saw. The four identical openings on the cylinder itself are actually normally blanked clean-out openings; the small flanged connection visible here in the center near the lower end is the cooling water inlet. Since no cooling water comes in contact with the main engine frame, we can classify this engine as a "dry block" engine.





The manual only shows a few locomotives, and all of them shown were built after ALCO left the group and went off on its own. Here we see two locomotives; at the top, Illinois Central 9000, a 100 ton 600 horsepower twin-engine box cab locomotive, and below is Bush Terminal 2, a 60 ton 300 horsepower switcher style locomotive. It is interesting to note that while the box cab design went away in favor of locomotives with narrow hoods, the characteristics of the locomotives built to the upper twin-engine design - namely, weight in working order of 100 tons and horsepower of about 600 - were established by this design and remained in production and competitive until several years after the end of the Second World War, at which time the competitive situation drove the horsepower ratings of 100 ton switching locomotives above the 600/660 HP level to 750, 800 and even higher. In other words, the original rating of the 100 ton unit conceived by ALCO-GE-IR in the mid 1920's remained useful and competitive for about 20 more years.

Ingersoll-Rand attempted to remain in the locomotive field only briefly after its original engine became non-competitive. It built its Model S, with the same bore and stroke but overall new construction and much higher rating which failed to meet any wide industry acceptance, and apparently exited the market after 1936. We hope you've enjoyed this brief look at this truly pioneering diesel engine.

{First in a series on the design and construction of diesel engines for use in locomotives.}

General Electric Wheel Slip U25-U36

{I originally wrote and disseminated this document in mid-2005. At that time, I placed it on file in a number of locomotive forums. I have updated the information in this document and it appears here in this form only; consider this version to supersede others extant.}

Wheel slip control in the General Electric Universal Series.

When General Electric began demonstration of the U25B, it was already aware that the railroads would have concerns about adhesion, considering the high power per driving axle. In order to mitigate these concerns, and give the locomotive true drag capability, GE chose to employ a piece of equipment which had already independently been under test in the US for several years (both by Westinghouse Air Brake and by New York Air Brake) as standard equipment.

This device was known as the Slip Suppression Brake Valve, or SSBV. The principle of the SSBV was that wheel slip could be corrected not by reduction of power and application of sand, but by an extremely quick application and release of the independent brake on the locomotive wheels. This device had already been installed experimentally on EMD units on the Western Maryland and had shown an ability to allow increased tonnage ratings in drag service, due to its ability to arrest slip with the locomotive still producing full power. The idea was that any brief track perturbation or weight transfer between axles which caused the slip would be passed fairly quickly, and so simply identifying the slip condition and arresting it without reducing power would not allow speed to drop further, as it would if excitation were reduced, albeit temporarily.

GE also chose to employ a new speed sensing system on the U25B which could provide better monitoring of axle speeds, through individual direct measurement. Normally, wheel slip relays in locomotives were picked up by voltage imbalance between traction motor leads. The new Axle Alternator system used a journal-box-mounted alternator on each axle, whose output was then conditioned into a usable signal for detection of slip, and for transition control as well. This system, with theoretically more rapid detection of slip / incipient spin, coupled with the SSBV to stop it, was supposed to allow unusually high factors of adhesion. Tests with the U25B prototypes actually did show much better adhesion (over the normal 18-20%) in drag service.

With this system, there was a backup; if the slip continued for longer than three seconds, then sand would be applied, excitation reduced (through action of relay and energizing of the ORS solenoid on the governor, which moved the load regulator toward minimum field position,) and the warning light and buzzer sounded. Incidentally, this was not the original design; General Electric 751 and 752, when operating in 1960 as the experimental, prototype U25B locomotives had the slip suppression brake equipment but did NOT reduce main generator excitation upon detection of wheel slip {ref. GEJ-3807, Operating Instructions General Electric Model U25B 2500 HP Diesel-Electric Locomotive - for road no’s. 751-752, page 44.} These units only gave a light and buzzer indication of slip coupled with SSBV operation, without sanding or generator excitation reduction. This design didn’t make it to production units.

Early on, each railroad buying the U25B also bought it with the Slip Suppression equipment since it was standard. However, some roads began to complain of pinion slippage and worn wheels. In brief, the operation of the U25B in mountainous terrain did actually lead to still-unfavorable wheel slip conditions, even with Slip Suppression. In the cases where Automatic Power Matching was employed, this condition was made less severe, but as this system derated the locomotive when excessive traction motor field temperature was reached, the advantage of the high horsepower was lost. The problem continued, and worsened with the U28B, especially on the Pittsburgh & Lake Erie, where U28B units were often used in drag service. General Electric was already aware that refinement was necessary. (It also developed an optional Pinion Slip Alarm at the request of the Louisville & Nashville, although GE’s stated opinion on the subject was that properly applied traction motor pinions did not slip -- a statement condemning the maintenance performed by the railroads.)

In 1964, GE began using new control equipment in the U25B. A new Type FL7 Adhesion Loss Detection Panel replaced the original 17FM190 panel; a new Type FL10 Speed Sensing Panel replaced the original 17FM191 Automatic Transition Control Panel. It appears that the purpose of the new equipment was performance related, although details are not given; these changes are found only by comparison of a number of manuals. One alteration is the addition of circuitry in the FL7 panel that attempts to detect synchronous slip, not addressed with the earlier model, and which only operates upon a simultaneous high speed signal from all axles. This particular protective feature would be improved upon in later locomotives.

During late U25 production, GE had made available an optional All-Electric Wheel Slip System. This was basically the same as the original system without the SSBV, and included instant triggering of the slip relay. One GE representative noted, a few years later, that the actual air valve in the SSBV system was “like any other air component -- you have to maintain it properly or it isn’t going to work.” It seems clear that GE felt that the original idea was still good enough to retain, but also noted that some railroads had continued to buy the system on later units (U28, U30) and that some did not, and might have credited improper maintenance of the equipment with its operational shortcomings.

In the U30, GE kept the options of either Slip Suppression Wheel Slip Control, or else All-Electric Wheel Slip Control, but augmented both with new circuitry designed to detect and correct conditions not detected or corrected by the early U25/U28 systems. The new system could detect synchronous slip of all driving axles simultaneously at low locomotive speeds, and could detect simultaneous high-speed wheel spin of all axles as well. Two different circuits were used, one for each condition, while retaining the Axle Alternator detection system to monitor axle speeds.

With the new system, normally fitted without the SSBV, the ORS solenoid on the governor was not used in conjunction with the wheel slip detection to reduce excitation and thus power. Instead, the completely new excitation system (developed for use with alternator-rectifier transmission) employed inputs from the wheel slip circuit cards to immediately reduce excitation by action of reducing the output of the pulse-width modulator used to supply field to the exciter. This system was both more sensitive and much faster. (With the SSBV, only a slip condition longer than three seconds duration would trigger excitation reduction, sanding and operator warning; without, either in U25/U28 or the new U30 units, these latter actions were immediate.) In later U23 units with GT-581 (U23B) or GT-586 (U23C) generators, the new system was altered to, in fact, return to use of the ORS solenoid.

One of the features of the Universal Series locomotives from nearly the beginning was a system called Automatic Power Matching which reduced locomotive output under adverse operating conditions, which theoretically also had the advantage of reducing wheel slip. In the U25 and U28, this system was not triggered until an over temperature condition was detected in the traction motor shunt field windings (indirectly, by voltage drop.) This system pulsed the ORS solenoid on the governor to force the load regulator wiper arm to assume, on average, a lower field strength position; the pulses or cycles occurred at about 15 times per minute. The Power Matching Panel for the U25B was part number 17FM211C1, and our shop manual for the NYC’s U25B units instructs the setting of the resistor on this panel to correspond to a generator load of 700V / 2000A or about 1876 horsepower. The system remained operative until a timer circuit cleared, which ran seven minutes. Engine speed remained responsive to throttle setting allowing full ventilating air to the traction motors.

Statements by GE engineers at the time indicated that this Power Matching was as much to protect their warranty-covered traction motors on the U25B as it was to match the units to those with which GE units would operate. Regardless, this was the first system of its kind in the USA. This system was standard equipment on U25 and U28 units.

In the early U30 units for what appears to be several months of production, this system may have been retained. Mid-way through 1968, the locomotive manuals begin to describe the addition of a further static control panel in the electrical equipment cabinets: the 17FL24 Power Matching Panel. This panel was used to condition the reference signal for the aforementioned pulse-width modulator to effect a (constant, non-pulsed, non-timed) reduction in power at lower speeds when the locomotive was operating in series-parallel only. It appears by mention in the manuals, and in various statements by GE officials, that on the U30 the system was optional; on later U33B units it was standard, and optional on the U33C. U36B and U36C units followed the same pattern.

This card caused a limit of reference current with decreasing speed down to about 8 MPH in the U33B, below which the full normal range of current limit was available for starting. Above this speed, the reference current was limited essentially until the locomotive made transition to parallel. (Field shunting was not used on these locomotives, but transition was employed.) GE felt that no limit was necessary at speeds above that required for transition, and in fact, the temperature-triggered system on early units was also nullified at the time the locomotive made the transition from series-parallel to series-parallel shunted field (which for the U25B typically occurred at about 19 MPH with standard gears.) In the early system, if the time limit for power reduction (7 minutes) was not expired and the locomotive made forward transition to series-parallel with shunted field, and then back, the limit was still present; if the time had expired, and speed increased and then dropped, it would be necessary to have another over temperature condition to trigger the Power Matching again. In the later units, the system always operated (if fitted) in series-parallel. Both old and new systems could be adjusted, by rheostat, to finely tune the desired amount of power reduction and thus the actual minimum continuous speed.

One further feature included in the U33 (and added to the U30 after this) was the introduction of a rate of change limit on excitation. With this circuitry, there was a limit on how fast the excitation signal could increase, and was in effect at all times, and for any action (throttle manipulation, slip recovery, load regulator action.) One GE representative referred to this as “rounding off the notches,” meaning that no abrupt increase in excitation, and thus alternator output, was possible. This further improved (theoretically) the ability of the locomotives to hold the rail, especially the four-axle units.

As we can see, the systems fitted to the GE U-series evolved over time, and the changes did not necessarily exactly coincide with model changes either. At the time that the above improvements were introduced, one further addition was in the works as regards the wheel slip system, which first appears in manual GEJ-3868, an electrical equipment manual which is the first to cover models U23, U30 and U33. This addition is sometimes referred to as the Rate of Change system, and is also sometimes referred to (especially by GE engineers and representatives) as the Power Tie Circuit. These terms are proven synonymous by this manual.

Around the time that EMD introduced its new 645 line of locomotives, there had still been outside research going on not directly connected with the locomotive manufacturers. One such concept was the use of direct measuring coils, mounted on the traction motor leads, which could detect small but instantaneous changes in actual traction motor current. This system was developed and tested by outside companies and various railroads, but EMD essentially adopted it about one year after the new 645-powered locomotives were introduced, as its IDAC Wheel Slip Control System.

General Electric was still employing the same axle alternator units as primary detection as had been used since the U25. However, the challenges of maintaining adhesion with the U33B were proving daunting, and GE added a similar system in concept sometime around the middle of 1968 in its ROC or Power Tie system. This required the addition of yet another static panel, the FM262 ROC panel, and ROC slip sensing transformers. The power tie was connected between the midpoints of pairs of motors when in series-parallel; because of this location, with all axles rotating at the same speed, there should be either a tiny amount of current flowing through this cable, or else (usually) none. If one axle begins to slip, the amount of current drawn by the sets of motors will change relative to each other, and this would then cause current to flow in this power tie. The detection of slip by this indirect method was more sensitive than the axle-alternator detection. The normal wheel-slip system as previously described was still retained, but special circuitry was included to reduce the effect of the relay normally operated by the old wheel slip system when the ROC system relay was picked up. The new system also included the design consideration that rapid and frequent small slips would cause a proportional slight lowering of excitation (and an even more tapered power recovery) which would allow the unit to maintain the highest possible power in the given rail condition. In parallel transition, the ROC system was completely cut out.

This new system did not in any way require the use of axle alternators. Within several years, GE had developed it to the point that the old axle alternator system was deleted, along with its supporting circuitry, and all wheel slip detection performed by coils; this was the Current Measuring Reactor system, or CMR system, and while this system is normally associated with the later “Dash 7” units, one will note that a number of orders of late Universal Series locomotives completely lack axle alternators (except one for speed indicator/recorder drive.) This indicates application of this CMR system. Reportedly, this system could react in one thirtieth of one second.

This concludes our investigation of wheel slip control as applied to the General Electric Universal Series. GE entered the market with the advantage of high horsepower per axle, and in a sense bet its fortune on the concept of high haulage capacity combined with high power and nominally similar weight. The one Achilles heel of this concept was the ability of design engineers to cope rapidly enough with adhesion difficulties as the horsepower race accelerated between the builders, and we have seen that GE was more than mildly active concerning modifications to the U-series over time to address this problem. While many have faulted GE for locomotive quality issues in this early period, it is clear that GE was making every effort to correct the problems and still move ahead in power, allowing it to retain a competitive position -- which in the end helped to drive ALCO out of the business.

Source material for this document includes not only a number of GE locomotive maintenance manuals, but a series of lectures delivered to conventions of the Railway Fuel & Operating Officers' Association by GE engineers over a span of years covering models U25 through U33.

Lima's mythical 2-12-6

Here, for the first time anywhere, we present the rumored but never seen legendary Lima Locomotive Works proposal for a 2-12-6 locomotive. Often cited as the genesis of the awesome 2-6-6-6's of the Chesapeake and Ohio and the Virginian railways, this design has remained an unprovable myth. No longer.

Presented during the above group's meeting in Chicago, the report was written by none other than W.E. Woodard, legendary locomotive designer, and at the time Vice-President, Lima Locomotive Works. Unable to attend due to poor health, the report was actually presented by Mr. H.W. Snyder, Mechanical Engineer of the Lima Locomotive works.

Many aspects of super-power locomotive design were covered in this thorough and intelligent presentation, but what interests us here is the section about reduced locomotive maintainance. Woodard, and Lima, were advocating unitary machinery supports, and tandem rod drives. These served to reduce the distance between cylinder centers, thus greatly reducing the bending forces on pins, rods, and frames. A 4-6-4 and a 4-8-4 are shown using these principles, but below we see the ultimate extrapolation of 2 cyl. power, the 2-12-6. Cylinder centers as shown are only 88 inches, with bending forces well within curent limits, and actually less than some locomotives already in service.

The grate anticipated was 151 sq. ft., needed to supply the enormous cylinders. Their goal was to be able to replace 2-8-8-2's with such an engine, developing more power on less fuel and water. This 2-12-6 embodied all the then current super power features. By estimate, it would have evaporated a very impressive amount of water for 1928, and with limited compensated cutoff would have been able to use that steam to provide power at speed. It is the natural progression from their 2-8-4 and 2-10-4 engines, without articulation.

So here it is. It wasn't just a type discussed somewhere. This was presented in front of the leading motive power men in the railroading world. This presentation was followed by another given by A.W. Bruce, Designing Engineer, American Locomotive Company, on "The locomotive of today and the future as a factor in fuel economy." Excellent company to be in, and in front of which to present this awesome design.






The table above was given in the report after the drawing. This table shows not only the capabilities of the proposed engine vs. that which it was designed to replace, but Lima's design philosophy at the time. The new engine might not be able to start a heavier train than the Mallet, but it could move the same trains much faster on less fuel and water. The concept of power at speed was well understood by this time, and just as 2-8-4's were made to replace 2-8-2's, and 2-10-4's to replace 2-10-2's, providing more boiler capacity than the previous types, so was the 2-12-6 designed to replace an even bigger type, providing the same power at speed increase.


A major consideration in locomotive design used to be "clearances". Probably still is! That is, how big a locomotive could be and still fit everywhere on the railroad that it needed to go. Very accurate measurements were taken by the railroad along their right of way, and these were supplied to the locomotive manufacturer. A template was made, and the finished locomotive had to pass through it in order to be accepted by the railroad.

Virginian's famous 2-10-10-2's actually were too large to be shipped on most railroads. They had to be partly disassembled for their trip. The reason was their enormous low pressure front cylinders. Their total width was too big for many roads. This was in some cases the limiting factor for compound locomotives. Simple articulateds solved the clearance problem of the big cylinders, but 2-cylinder simple (non compounded) locomotives like 2-10-4's could press clearance limits with their large cylinders too.

Lima's unitary machinery support concept, used on the 2-12-6 proposal shown above, lessened the distance between cylinder centers. This allowed very large cylinders, in this case actually well forward of the first pair of drivers AND THE LEAD TRUCK (!!) without having an overly wide locomotive. Without this innovation, such a locomotive would have been impossible.

Another thing this design accomplished was to reduce the bending forces exerted on the cylinder saddle and main drive axles. This is because the main rods are closer to the wheels themselves, using shorter journals than would otherwise be possible. As the report states, reduced forces lead to reduced maintainance, an important factor in railroading. Locmotives in the shop can't make any money hauling trains. Lima's design innovations not only allowed for bigger, more powerful locomotives, but also ensured they would be out on the road hauling trains more often than not.

Would these locomotives have been successful if they had been built? We can look at Union Pacific's 4-12-2's for an answer. Built to replace compound Mallet locomotives, the 4-12-2's were expected to haul about the same trains as the Mallets, but faster and on less coal and water. They did indeed prove that they were able to do so. In this case, an unorthodox wheel arangement (the 4-12-2) was the right machine for the job. One can expect that had the 2-12-6 been made, and used in a similar way (as Lima's comparison targets) to replace Mallets, the results would have been at least the same if not better.

General Electric FDL Diesel Engines - 4

FDL-16F

This engine seems the hardest to quantify in terms of initial changes using the available manuals although some things are fairly clear. What seems clear is that by at least 5-70 a new engine cross section drawing (GE E-16188) has appeared in the manuals; the new Diesel Engine Mechanical Service Manual GEJ-3869 contains this drawing at that date for, we believe, the first time and this manual is the first to cover the 3600 HP 16-cylinder engine for the U36 series; thus the first and most obvious change is the increase in fuel rate for the FDL-16F at 3600 HP.

Other locomotives already in production soon changed to use of the F engine, including the U23 and U30.

In terms of manufacturing alterations in the "F", one change that clearly was due to the uprating of the engine was the provision of a second oil drain hole in the underside of the piston crown cavity on the pistons fitted to these engines. GEI-81976, Instructions for Connecting Rods, Bearings and Pistons (and which is a component part of large binder GEK-30130A) instructs that earlier engines should be modified by drilling the second set of drain holes into the piston crowns. These pistons, it is important to note, are NOT yet steel-capped pistons.

A new heavy walled cylinder liner also appears in this time frame, omitting an external jacket (the old style is called "belly band liner" in GE manuals) and thus making the cylinder assembly essentially revert to a wet block construction, since the outer water boundary is again the inner boundary of the cylinder assembly. In the same parlance this new liner is called the "Annular Groove" liner, and on this style the interior was either chrome plated (requiring iron piston rings) or Tufftrided (requiring chromed piston rings.) Further, it appears that on the "F" the change to holding the cylinder head in place using the liner, instead of bolts from the head to the cylinder jacket or cylinder assembly, was made (although this may have occurred late in "E" production and during overhaul GEK-61273 instructs for the omission of these bolts on all engines... Note twice now the instruction to make alterations to in-service engines that essentially convert them to "F" engine features.)

At least one railfan oriented publication stated (quite some years back) that the U34C introduced steel-capped pistons. This may in fact be the case, especially since the U34 is listed in GEK-30130A as being equipped with the FDL-16F. However, since the date of publication of this particular table is 2-76 and reprinted 9-77 this may also reflect upgrading of all of the engines in this model of locomotive to "F" status. One cannot be sure, at least from this material.

1973

According to the manuals, a number of changes were made to the production FDL diesel engines in 1973. This appears not to have made a difference in the letter designation of the diesel engines, however. These changes are spread throughout the various instructions and descriptions and appear to be a number of small refinements all essentially implemented at one time.

Up until mid-1973, all FDL engines had incorporated intake valves with 45 degree intake valves (the angle of the seating surface to the valve centerline.) Apparently, according to a GE technical paper in our collection, valve seat recession was experienced. The modification to remedy this was to alter the intake valve design to 15 degree seating surfaces and this occurred in mid-1973 on some engines, and by the 10-78 print date of GEK-61273 all production engines incorporated this change. This same instruction orders that no exhaust valves with a date stamp prior to 8-68 (and those with no date stamp at all) should be remanufactured, but instead scrapped due to questionable quality.

A modification to the governor drive assembly occurred at this time, and the new drive with an adaptor was then furnished any time the complete previous assembly was requested as a replacement or spare for engines in the field.

Steel crown pistons, using a steel cap bolted to an aluminum body, probably appeared in testing applications on production engines near the inception of the "F" series initially, as hinted at by the fact that the GE illustration number for the steel crown piston is fairly close to the illustration for the new diesel engine itself (which does NOT include these pistons.) It seems that by the 1977-1978 general date of the Conrail manual that is our primary source, these were production standard for all FDL engines in 8, 12 and 16 cylinders.

Also at this time all FDL engines were changed to a fuel header pressure of 39-41 psi. These used the same (large) fuel pump system as previously employed. Older locomotives could be altered to use the new pressure but had to have the fuel racks reset; the locomotive had to be on a load box if the low pressure, large pump system in more recent locomotives was to be converted.

There appear to be numerous other small changes; these are only a few at the time. We'll now turn briefly to a look at the FDL-12 series in domestic U-series locomotives.

FDL-12

The FDL-12 in all references had no lower model delineation than "B" - so that the first FDL-12 model in GE locomotives by these tables (which never give dates) is FDL-12B. This seems to correlate in some way to there being no sixteen cylinder engine with the letter "B" so that in the early days of the Universal series (for export) and then the U25B, the A engines were 16 cylinders and the B engines were 12 cylinders. (Interesting that the "A" variant was for the domestic U25, which appeared later - giving some further credence to the wide assertions that GE intended to enter the domestic market from the start.) This slightly complicates correlation of engine models, though. It appears that after the early production, the FDL-12 used the letter B and D for export models U20 and U22, model C and F for domestic U23 models, and model D for export models of U23 and U26.

Item: The engine model listed for the U50C is FDL-16D, at 1050 RPM maximum.

Further Item: We know from manual evidence that the U50C, and from first hand operator evidence (thank you, Noel Weaver) that some of the Penn Central U23B units used a modified engine speed schedule whereby the engine operated at half speed in notches 1 through 4 and full speed in 5 through 8, with variation in tractive effort by excitation only. This engine speed schedule or description of any such NEVER appears in this Conrail manual; we imagine this variation to be quite rare as a result of this finding.

Whatever the case, the 12-cylinder engines are covered by this same large manual and delineations are almost never made in the material so that we can be sure the same lineage of modifications occurred to the FDL-12 (and also the FDL-8) even if the engine model letters did not match up, at least for the first few years.

We hope you've enjoyed this series on the known (or rather, UNknown until now) model delineations of the GE FDL series engines. I have many engine illustrations to show and those will be coming along shortly.

Baldwin - BLH Diesel Engines in photos -2

If you haven't seen our first installment in this series, please take a few minutes to find it and read it to get the whole story -- and the piece (all text) on the mechanical history of the 600 series engine won't hurt either. We are not going to show EVERY photo in our whole collection, but will show the majority.

Let's pick up our study of engine photos with the beginning of 600 series engines that were released for service .. in other words, right after the prototype engines.

This photo comes from the Baldwin magazine, first quarter 1946 in which the new 3000 HP locomotive for the Seaboard Coast Line is announced. The photo is of one of the two 1500 BHP 608SC engines constructed for use in this locomotive; this shot appears to be the only shot we are using here that is duplicated anywhere. (Kirkland's book uses a copy from the same negative, apparently.) Again, notable are the lube oil filters mounted to the side of the engine.

Bulletin 249 (no date) was an advertising brochure produced by Baldwin for its 600 series engines for all types of service. Even with no date, it's easy to tell that it's early because the two engine shots depict the engine-mounted lube oil filters like we've been seeing all along. This engine is the production version of the 606NA, which was rated 660 BHP.

Here, also from Bulletin 249, is the short-lived production 608NA engine, rated 1000 BHP. This engine was not built for long before Baldwin decided that a six cylinder turbocharged engine with identical rating was a better choice than this eight cylinder normally aspirated engine.

This smaller image is from Baldwin DE-100, Diesel Engine Manual / 600 Series. This was the very first manual for these engines, and shown is the early production 608SC engine identical to that shown earlier as depicted in the 1st quarter 1946 Baldwin magazine. 1500 Brake Horsepower, eight cylinders, turbocharged.

Now, we'll end up our look at these engines - at least externally - with the final round of engines built by Baldwin, which of course by this point was Baldwin-Lima-Hamilton. (Note; The company did build the Hamilton T69SA and T89SA engines after the merger, and also used Superior engines for export locomotives; we'll be showing those engine ranges in future articles.)

Baldwin 606 engine. Six cylinders, normally aspirated. 875 brake horsepower; 800 horsepower for traction.





Baldwin 606A engine; 1315 brake horsepower, 1200 horsepower for traction. Six cylinders, turbocharged. Final turbocharged six-cylinder variant shown in final Baldwin 600 series manual, DE-111A.



Baldwin 608A engine; 1750 brake horsepower, 1600 horsepower for traction. Most powerful engine employed in any Baldwin or BLH diesel locomotive.

SO, there's our quick look - mostly externally - at the range of Baldwin / BLH diesel engines to go along with the posted discussion on the development and progression of the 600 series engines. I hope you've enjoyed it.

Baldwin - BLH Diesel engines (VO, 600 series) in photos 1

Yesterday, I made a post about the mechanical progression of the Baldwin 600 series diesel engines, which really is an updated post of a piece I wrote about five years ago or so and put on my original website. I've reproduced it here, minus the photos as I mentioned -- but today I've got FAR MORE photos ready than that original site ever had.

One note - These photos come from a variety of sources in our collection, namely the VO Diesel Engine Maintenance Manual, BLW/BLH manuals DE-100, DE-104, DE-111 and DE-111A (600 Series Diesel Engine Maintenance Manuals), a Baldwin Magazine from 1946, an undated Baldwin-Westinghouse sales brochure, and BLW Bulletin 249 which is a sales brochure for the 600 series engine for various kinds of applications (in other words, not just for locomotives but for stationary power.) All original source material.

Even though we didn't discuss the VO engine in the previous post, let's start with a few views of this engine.

Here is a three quarter shot of an eight cylinder, 1000 BHP Baldwin VO engine. Note that this engine uses the main production version of the engine frame that only includes a half-circle mounting for the main generator, which Baldwin found problematic and changed after the war when it was allowed to do so. Note also the two lube oil filters on the side of the engine; these are a hallmark of VO and early 600 series engines.



Here is a cross section view of the Baldwin VO engine. Readers should immediately examine the cylinder head, and notice the ovoid (egg-shaped) combustion chamber contained entirely within the cylinder head, and connected to the cylinder working volume by a cylindrically shaped passage. All of this is cast into the head. This antiquated design came from the days when atomization of fuel was problematic; this could be remedied by forcing all the air into a small volume, with induced swirl, which would start combustion in the small chamber upon fuel injection and heat all of the mixture to the point that any larger fuel droplets would hopefully both atomize and burn completely as they spread into the working cylinder. What this means, though, is that a large amount of heat is liberated in the cylinder head - given to lube oil and cooling water - and that it's impossible to cool this combustion chamber with intake air. This makes the heads run hot and makes a definite ceiling on fuel rate due to liberated heat. This is why Baldwin had to convert to (more modern, more conventional) open combustion chambers with its new 600 series engine in order to get any increase in power.

Next, at left, we have a late VO series 8-cylinder 1000 HP engine. Note the late-model alteration to include a main engine bed that has large extensions or arms to mount the generator much more solidly than the half-circle flange used previously. Note also the lube oil filters. This engine looks very much like the later 608NA but the sure way to tell is to look at the fuel pumps and push rod tubes. On the VO engines, the fuel pumps are on the cam deck between the intake and exhaust valve push rod tubes. On all 600 series engines, the fuel pumps are BESIDE the push rod tubes. This always works as an ID feature.

Baldwin developed its new 600 series engines while the war was in progress, using some new components and some VO components. Two fascinating shots are found in a Baldwin-Westinghouse sales brochure we have. One of these engines has been seen before in Kirkland's book in a different shot; the other one has not.

This is the shot we're sure hasn't seen light yet. This is certainly the prototype 608NA engine. Note the clear 600 series fuel pump and push rod arrangement, but note the use of the half-circle flange mount for the generator and the two lube oil filter tanks. Note also the four exhaust stacks. We can guess a bit more after seeing the next picture.

This is the prototype 608SC engine. This engine is shown, in a different picture, in John Kirkland's book and in that book Kirkland mentions that only this engine was built this way - with a mix of old VO style and new 600 style components; again note the half-circle flange mount for the generator. Surely the previous photo contradicts this unless we assume that the engine was first built and tested as a normally aspirated, 1000 BHP unit and then altered and turbocharged to produce the 1500 BHP prototype seen here and in Kirkland's book. This assumption seems safe enough, but again it is only my assumption. From an engineering standpoint it would make perfect sense.

Next post in this series will continue with the 600 series engines in every variant we can get a photo of, so keep looking back.

Baldwin - BLH 600 series engine history

THIS CONTENT was originally published on my locomotive site a number of years ago. I've decided to put it back on the net on our new site. I have totally cut and pasted it from my own site page at the internet archive but the PHOTOS are not included. I will try to get all of those, and some more, including shots we have of some of the prototype engines that haven't seen the light of day before, up on this blog in the near future. So please ignore photo references in the text.

Baldwin / Baldwin-Lima-Hamilton 600 series diesel engines 1946-1956.
Following the failure of its multi-engined road locomotive concept, which effectively ended the Baldwin 400 series engine's future, the company decided to center future locomotive production around a thoroughly redesigned version of the VO engine, to be known as the 600 series. Paramount to the new engine's design was the ability to accept turbocharging; the cylinder heads had to be totally redesigned to eliminate the integral combustion chambers of the VO in favor of the modern open chamber design (in which fuel is injected directly into the cylinder volume.) New, saucer-top pistons were developed. The entire engine structure was redesigned and reinforced, including much heavier crankshaft and connecting rods; the new engine would be required to develop a rated 1500 HP, which was 150% of the rating of the previous 8-cylinder VO.

The new engine series was phased into the various locomotive lines in a slightly hodge-podge manner. The basic details of the new engine lineup immediately after the end of the Second World War are seen below. Note that all 600 series engines were 12.75" bore, 15.5" stroke and ran at 625 RPM maximum.

606NA 6 cylinders, normally aspirated. BMEP = 70.6 psi. 660 brake HP.

608NA 8 cylinders, normally aspirated. BMEP = 80 psi. 1000 brake HP.

608SC 8 cylinders, turbocharged (Elliot BF44.) BMEP = 120 psi. 1500 brake horsepower. (This engine is pictured at left, in its earliest production configuration. From Baldwin Diesel Engine Manual DE-100, published 1946 and revised 3-26-47, 4-9-47, 2-1-48, 5-1-48.

Baldwin decided, shortly, to replace the 608NA engine with a new, turbocharged 6-cylinder engine. This engine is added to the aforementioned DE-100 manual in the 3-26-47 revision; details for it are as follows.

606SC 6 cylinders, turbocharged (Elliot BF40, known as "two exhaust pipe" type, or Elliot BF34, known as "three exhaust pipe" type.) BMEP = 106.7 psi. 1000 brake HP.

It should be noted at this time that Baldwin was advertising and rating its locomotives based upon the brake horsepower rating of the diesel engine. ALCO-GE was also using this system with its locomotives powered by 539 engines, but had decided to rate its road locomotives, powered by 244 engines, using the "horsepower for traction" rating which indicates power delivered to the generator. This theoretically placed Baldwin at a slight power disadvantage, which it eventually corrected later.

The original DE-100 manual stipulated that main bearing alignment be checked at intervals of once per year, or every 300,000 miles. The revision of 5-1-48 shortened this to every six months or 50,000 miles. The 5-1-48 revision becomes more specific about procedure of mounting the generator to the engine and checking its alignment. The engines were still using shimmed main bearings at this time; drawing D-1004 in DE-100 shows the comparative placement and thickness of the bearing shims. Some of the locomotives still used lube oil radiators; some used the full flow oil filters, some the bypass type. The 2-1-48 revision appears to be the one to include the three-pipe, or BF34, turbocharger for the 606SC. In general, it is clear that, at this time, the engine had been improved from the VO, but many design details were being altered in the period 1946-1948 and that some of the original sources of complaint (oil radiators, shimmed crankshaft bearings, for example) had still not been eliminated when the 600 series engine appeared.

Baldwin Diesel Engine Manual DE-104 was the next manual issued, and while the first printing date is not known, it was revised in 5-15-50 and 11-1-50. It is assumed that the original printing was likely in late 1949 or early 1950. In this manual, it is made apparent that numerous changes have been made to the engines. Probably the most important to modern railfans, and the least known, is the fact that Baldwin changed over at this time from rating its locomotives by the brake horsepower of the engine to rating the locomotives using the newer "horsepower for traction" method. Baldwin increased the actual power output of the engines without altering the advertised ratings of the locomotives. Below are the 1950 specifications for the three engine models in production (first built in January 1950 and contained in DE-104 on a revision page dated 5-15-50.)

606NA 6 cylinders, normally aspirated. BMEP = 88 psi. Compression ratio 14.88:1. 825 BHP. HP for traction 750.
606SC 6 cylinders, turbocharged (as before.) BMEP = 120 psi. Compression ratio 13.45:1. 1125 BHP. HP for traction 1000.
608SC 8 cylinders, turbocharged (as before.) BMEP = 130 psi. Compression ratio 13.45:1. 1625 BHP. HP for traction 1500.

New, Tri-Metal shimless crankshaft bearings replaced both the (shimmed) gridded and babbitt types used prior. Bearing dimensions remained the same, as did valve dimensions in the cylinder heads. The following are the given cylinder conditions at full load: 606NA max compression pressure 540 psi, max firing pressure 1015 psi. 606SC max compression pressure 720 psi, max firing pressure 970 psi. 608SC max compression pressure 750 psi, max firing pressure 1000 psi. Maximum exhaust elbow temperatures in the same order were given as 950, 850 and 900 degrees; thus, the normally aspirated engine had the highest exhaust elbow temperature. Valve timing for the engines depended upon whether or not they were turbocharged, and also upon whether or not the engines had the older "Saucer top" pistons with a concave piston crown, or the new "Hesselmann" pistons, sometimes referred to in the field as "Mexican Hat" pistons, as these had a depressed top portion with a pointed, raised center. Fuel injection timing also differed between piston types as well. Thus, for six-cylinder engines there would have been four different camshafts available (normally aspirated with saucer pistons, normally aspirated with Hesselmann pistons, turbocharged with saucer pistons, turbocharged with Hesselmann pistons.)

Baldwin issued its Diesel Engine Manual DE-111 on 9-15-50, which covered the next round of revisions to the 600 engine. The largest change was the inclusion of a substantially larger and heavier crankshaft; all of the bearing bore sizes increase, and lifting weight of the crankshaft increases as well. It appears that upon issuance, Baldwin was beefing up the bottom end of the engine to accept a further power increase. This happened shortly thereafter. The following ratings are included in this manual, on a page dated 6-15-51.

606 6 cylinders, normally aspirated. BMEP = 93.5 psi. 875 BHP. HP for traction 800.
606A 6 cylinders, turbocharged (Elliott H503.) BMEP = 140 psi. 1315 BHP. HP for traction 1200.
608A 8 cylinders, turbocharged (Elliott H704.) BMEP = 140 psi. 1750 BHP. HP for traction 1600.

Cylinder conditions at full load are given as follows: 606 max compression pressure 540 psi, max firing pressure 1120 psi. 606A and 608A max compression pressure 690 psi, max firing pressure 1120 psi. Max exhaust elbow temperature 1000 degrees F for normally aspirated engine, and 925 F for turbocharged engines. The increases in power over the time the whole 600 series was in production had been produced by increase in fuel injection amount, involving both volume and timing, as well as boost pressure and thus scavenging effect and compression pressure. No increase in engine speed was needed to increase from the 1000 brake horsepower of the 608NA all the way up to the 1750 brake horsepower of the 608A.

At the very late date in Baldwin history of 2-1-55, manual DE-111A was issued to cover further revisions to the engine. These changes were very slight -- including changes to the crankcase breather design, engine air filter design, and others. One change of note was that the engines themselves became several hundred pounds lighter, for reasons which are not explained. This manual is also the first to contain a complete section on engine speed control applicable to all optional setups, including both types of air throttles available (D-1 and CE-100) as well as the 8-step electric throttle, and also includes data for the UG-8 and PG types of Woodward engine governors. (Most Baldwin manuals are specific, and thus there is a wide variation of manuals --- this is why this one, applicable to any optional combination, is unusual.) Looking through this manual reveals that the vast majority of important changes had already occurred prior to a date of 1953 (some of the pages in this manual carry this date) and most likely all of the last-generation changes physically date to 9/50, with the last uprating likely 6/51.

There you have it -- the complete breakdown of important evolutionary changes to the post-War Baldwin / Baldwin-Lima-Hamilton 600 series diesel engine. It is apparent that Baldwin continuously tried to improve their product, but for too many railroads it was not enough. Even though the late locomotives were greatly improved in reliability, the serious shortcomings of the VO and very early 600 engines caused many railroads to abandon Baldwin as a serious supplier of diesel locomotives.