Saturday, January 18, 2014

General Electric's 1977 Series Locomotives

What railfans today commonly describe as the "Dash 7" or "-7" line of General Electric diesel locomotives was announced late in 1976 and was described at that time by GE variously as the "1977 Series Locomotives" or else as the "New Series Locomotives."  This new line of domestic diesel-electric road locomotives was advertised in GE sales brochure GEA-10016, published 11/76 (1000 copies); the illustration above is from this brochure, and its cover is reproduced below.

The line originally included eleven models, which can be seen on the cover of the sales brochure above; this is not uncommon knowledge.  What is uncommon knowledge is what the New Series actually introduced to the GE line, and what it did not; further unstated anywhere is the origin of the design evolution.
"A New Industry Standard."
General Electric states in the introduction to this brochure that the New Series Locomotive was "the result of an intensive three year design and manufacturing program to further improve the quality of General Electric Locomotives."  This process was of course continuous with GE locomotives already; over the years GE had included product improvements and refinements (as well as power uprates) into locomotives actually built in series production for railroad service, but at the same price as conventional units in the order (for example, GE included two 3300 HP U33B locomotives in the midst of a New York Central production run of 3000 HP U30B units as "pre-production field test units") for the purpose of field testing improvements.  This process had begun with the U25B and continued through the early 1970's; for example, the steel crown piston was introduced first in 1970 on high horsepower models and eventually was applied to all models at all ratings.  (In fact, the original cast iron piston was allowed to go out of production so that, by the time of a 1983 GE publication in the collection, the iron piston had been unavailable brand new "for several years.")  What was different, apparently, with this New Series Locomotive line was the concentration of overall effort from the front of the locomotive to the back in a short period of time.
The brochure tells us of two new periods of improvement. Phase One saw GE perform what is described as "an in-depth study" with its customers which resulted in the development of "over 60 product improvements" that were incorporated into the locomotives in 1975 "on a scheduled basis," which simply implies that improvements were phased in as they were ready.  Phase Two consisted of all of the alterations found in the New Series Locomotive lineup; it was considered also to be complete as of the 11/76 publication date of the sales brochure.
"Phase One"
General Electric issued Specification 3860 in 1975, entitled "1975 Product Improvements."  Brief details of this specification are included in GEA-10016 as is an illustration of the specification itself, seen below.

The list of improvements is wide ranging.  58 are listed in GEA-10016 from Specification 3860; these are listed below.  These are not explained but rather are simply listed; most are obvious, but for those which are not I will include a brief description from other official GE publications.

1.  New Platform Sump-Drain System
2.  Newly Designed Braking Switch
3.  Easy Fuel Pump Motor Brush Access
4.  New Self-Cleaning Primary Dirty Air Outlets
5.  High Reliability Governor Plug
6.  Longer Life Cab Gauges
7,  Blue Control Card Labeled When Adjustment Required at Time of Installation
8.  Built-in Engine Barring Over Device
9.  Adequate Drains for Exterior Lights
10.  New Engine Cab Door Latches Provide "Positive" Locking
11.  New Hatch Latch Eliminates Damage to Fuel Lines
12.  Lower Lube-Oil Fill Mark
13.  Cylinder Hold-down Bolt Inserts  (WD note:  This means that inserts were shrunk fit into the engine frame, into which the cylinder hold down bolts threaded; previously, the hold downs were studs threaded directly into the frame itself.)
14.  Dynamic Braking Grid Slag Catcher (WD note:  This catches melted dynamic brake grid material, should this occur due to fault.)
15.  Engine Overspeed Link Redesigned
16.  Cleaner Air Supply to Increase Air Compressor Filter Life
17.  Improved Oil Filtration
18.  New Turbocharger External Air Seal Arrangement
19.  New Fuel Filter Drain Valve
20.  Improved Gardner-Denver Compressors
21.  "B" Platforms Strengthened
22.  Engine Systems Monitor (ESM)
23.  Improved Accessibility to Engine Governor
24.  Settings Now Included on Electrical Schematics to Assist Maintenance Personnel
25.  New Voltage Regulator
26.  Improved Power Rectifier Panel
27.  New Control Compartment Drains
28.  Improved Fasteners for Engine Air Filter Doors
29.  Improved Accessibility to Electric Heat Blower Motor
30.  Test Points Built-In and Data Provided for Maintenance
31.  Removable Cab Heater Headers to Facilitate Core Cleaning
32.  Alternator/Generator Improvements
33.  High Reliability, "Static" Time Delay Relay
34.  Improved Power Cable Labels for Quick Identification
35.  New Governor Cables
36.  New AAR Controller Slide Out Feature
37.  New Labels to Facilitate Reverser and Braking Switch Maintenance
38.  Addition of Cooling System Test Points
39.  Toilet Water Tank Assembly Simplified
40.  Re-Orient Air Valves for Operation Safety
41.  Instruction Plate Added to Facilitate Engine Air Filter Maintenance
42.  Teflon Tape Used at Pipe Connections
43.  Small Resistors Labeled to Aid Troubleshooting
44.  Bolting Ears Added to Engine Air Discharge Elbows for Maximum Performance
45.  New Fluid Amplifier Gasket Material Reduces Leaks (WD note: the fluid amplifier assembly directs water to and from the radiator cores.)
46.  Inspection of Engine Bonded Rubber Drive Simplified
47.  New Fuel Booster Pump Seal for Ease of Assembly
48.  New Water Pump Seal for Longer Life
49.  Two Seals on Lube-Oil Filter for Longer Engine Life
50.  Engine Master Rod Cap Assembly Simplified
51.  Captive, Fast-Action Fasteners Added to Control Stand Access Doors
52.  Fuel Filter Tank Threaded Center Tube Eliminates Rough Weld
53.  Longer Life Cylinder Head Cross Head Guide O-Rings
54.  New Engine Governor Water Diaphragm Material for Longer Life
55.  Lubrication of Engine Cross Rocker Bushings Improved
56.  New Valve Spring Seat Design Extends Cylinder Head Life (WD note: This was referred to in engine manuals as the 'spectacle style' seat.)
57.  15 degree Intake Valves for Reduced Valve Recession (WD note: Started mid-1974.)
58.  New Gasket Material for Longer Life Water Jumper

It should be noted that these improvements are not the XR-series changes, nor are they associated only with New Series Locomotives.  These were applied during the two years prior to the announcement of the New Series and were incorporated in U-series locomotives.

"Phase Two" or the New Series Locomotive / 1977 Series Locomotive

The second round of improvements included five major areas of alteration to design and fifteen further changes to the locomotives.  Some of the 15 further changes had previously been either field tested or offered as extra-cost options (for example, electric cab heat) but now these 15 were incorporated in all locomotives "at no extra charge."

The five major areas of improvement were the following:

1.  The air compressor was moved off of the pedestal supporting the radiator fan gear box, and into a new small compartment of its own separate from the radiator cab.

2.  The arrangement and orientation of the lube oil filter, lube oil cooler and engine water tank was altered and improved.

3.  Only on 4-axle units, the equipment blower was moved into the radiator compartment.  (All U-series locomotives of models U25B and U25C, as well as U28B and U28C locomotives built through about 1/66 had their equipment blowers in the radiator compartment although these older units had a very different arrangement.)

4.  High and low voltage components were separated into two different control compartments - one above the frame, behind the cab and one below.

5.  GE included its interpretation of the AAR Clean Locomotive Cab layout which itself incorporated 18 "significant modifications" to the locomotive cab

I will show a couple of illustrations that point up some of these alterations physically in the New Series Locomotives.

Above, we see the rear or "No. 2 end" of the New Series Locomotive.  A B-B or four axle unit is depicted at top, while a C-C or six axle unit is depicted below.  Immediately obvious is the fact that the air compressor is now in its own compartment, which "isolates the unit from road dust, eliminates oil and oil vapor from the radiator compartment, lessens the chance of winter freeze-up" and also ensures the air compressor a supply of "warm, clean air."  In addition to this change the water tank is redesigned, and no longer supports the oil cooler; the oil filter is reoriented to ensure drainage; the oil filters now have ten instead of eight to stretch changeout time, as well as other changes and improvements.  Note that the equipment blower is behind the radiator fan gear box on the B-B units; this was necessary to allow room for the entirely new layout behind the operators' cab, which we'll see next.  The six axle units had more than enough room to allow the changes without moving the blower.

Above is the New Series Locomotive cab arrangement, incorporating AAR Clean Cab concepts.  The AAR locomotive controller (GE model KC-108) had been in use on GE U-series locomotives since 1972 and of course was incorporated in this design, but access to it and maintenance of it were improved.  The number keys on the illustration are for the following features:

1.  Protective covers over windshield wiper motors
2.  Soft rubber grips on windshield wiper motor handles
3.  Outside access to road number lights and headlights
4.  Flexible hinge guards on locomotive cab doors
5.  Main cab door closure bars
6.  Padding on the upper inside frame of cab doors
7.  Padded engineer's sun visors
8.  Rounded sliding cab window latches
9.  Soft-resilient rubber covered horn handles
10.  Side cab windows of Lexan
11.  Exposed main cab edges have been rounded
12.  Toilet compartment doorways of minimum dimension
13.  Floor drains, one way ventilators and waist-high washable walls have been installed in the toilet compartment
14.  Standard dimensions for water cooler alcoves
15.  Standard location of conductor's emergency brake valve
16.  Radio control head has been recessed in the control console
17.  Benelex Scuffcote floor covering
18.  Wiper valves and light switches have been recessed in the main cab ceiling

In addition to the totally new arrangement (which moves the toilet to a new compartment behind the cab, and incidentally also incorporates electric cab heat as standard equipment on all locomotives - although side strip heaters were not standard) described here, low voltage and low heat electrical components were moved to a compartment above the running board and behind the cab.   This compartment was cooled by locomotive equipment air, but had its own secondary air filters as well.  This move offered greatly improved access and longer component life since all components in both lower and upper compartments were less crowded, as well as "adequate space for customer options."

Earlier I mentioned that there were five major changes to the New Series Locomotive and fifteen additional equipment modifications.  The additional 15 changes were as follows:

1.  Copper power cables, replacing aluminum
2.  Alternator idler gear bearing redesigned with ball bearings instead of needle bearings due to previous design not providing the expected service life
3.  Grooveless lower main crankshaft bearings in all engines
4.  Water header of 12 cylinder engines raised up to height of that of the 16 cylinder engines to improve access to exhaust manifold
5.  Steel alternator slip rings for GTA-11 alternator (on extended field test since 1970)
6.  Electric Cab heat
7.  Babbitted crankshaft thrust bearing surfaces (similar to main bearings) for longer life
8.  New engine compression release valve design
9.  Improved overspeed governor
10.  Radiator clean-out panels (these are the small rectangular bolted panels under the radiator "wings" and above the radiator intakes on New Series units)
11.  Power Diode Retention Hardware - ensures diodes remain firmly attached to heat sink, ensuring heat transfer and extending life.  Previous design "had tendency to relax in service."
12.  Lexan side windows in cab - impact resistant windows for crew protection.
13.  Improved lube oil relief valve seat - now stainless steel to improve life, due to resisting wear
14.  Winter-Summer Engine Air.  This design feature incorporates a damper, manually positioned, that allows warm engine compartment air to mix into the engine intake air in winter "to provide more reliable winter operation."  This door would be repositioned in summer.  Interestingly, this device is mentioned nowhere in a slightly later Operating Manual for New Series Locomotives, GEJ-5729C, dated 5/79.  It may have been deleted.
15.  Oil and Water Piping Thermometer Wells to allow quick verification of temperatures.

External features and final comments.

Most railfan websites have concerned themselves primarily with external features visible on this line of locomotives which distinguish them from earlier U-series locomotives - namely, the widening of the engine cab (or hood) toward the rear and the provision of identical radiator compartments on all units regardless of horsepower rating.

Above is the side view of the B23-7 locomotive from GE Specification 3530D, dated 2/77.  (The hood lines, and ground, should be level, but I'm unable to use a scanner on this somewhat delicate document and was forced to simply photograph it - thus, it wasn't perfectly flat.)  Notable are the wide radiator compartment at the top, or "wings," which on the U-series had appeared only on U33, U34 and U36 models.  Also apparent are the new arrangement of radiator compartment intakes as compared with late U-series units and the small rectangular radiator clean out access covers.  This specification for the B23-7 and GE Specification 3390G for the C30-7, dated 2/77 (and thus both very early for this line) both clearly indicate that dynamic braking was included as standard equipment on the units, with extended range dynamic braking being an option.  This is not listed as a change to the product line per se in any of the New Series Locomotive sales material, but seems significant to note from a sales standpoint.

Above is a side view of the B23-7 from GE Specification 3530E, which interestingly has no publication date anywhere but is the next after that depicted above.  (Again, same disclaimer about lines should be straight!)  This locomotive has been modified to incorporate an exhaust silencer stack and to remove the oval side cab windows - changes across the entire New Series in 1980.  Dynamic braking is still standard.  A number of other features have changed, particularly the traction motor gear ratios, but the locomotive is largely the same product.


•Railfans should be aware that massive changes to very complicated manufactured products such as diesel-electric locomotives are not undertaken lightly, and that in many cases what has been printed in railfan press over the years is not completely indicative of the actual progression of developmental advances in these machines.  Until now, most railfans would have been led to believe that the major changes in the "Dash 7" GE locomotives (a name that you will notice GE did not, and does not use referring to its own products in these publications) centered on the oil filter / oil cooler and some miscellaneous reliability / maintenance improvements.  My purpose in writing this article (and in reviving the long-dormant blog on which it's posted) is both to correct the written "history" of this line, and to try to get railfans to think more mechanically and be more curious about reality and history as it really did occur.


"1977 Series Locomotive - A New Industry Standard."  GEA-10016, 11/76

B23 Locomotive Specification 3530D  2/77

B23 Locomotive Specification 3530E  no date

C30 Locomotive Specification 3390G  2/77

Operating Manual - New Series Diesel-Electric Locomotive GEJ-5729C 5/79

GE Locomotive Training Manual, undated.


  1. Thanks for this great share. This site is a fantastic resource. Keep up the great work here at Sprint Connection! Many thanks.

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  2. Let me join the previous commenter: THANK YOU! (And, as a fan of GE locomotives: double thank you for your choice of topic in reviving the blog!)

    ---The drawings on the cover of the sales brochure (second inset from top) seem to be the same as those in the operators' manual on George Elwood's "Fallen Flags" site: note that the B23-7 is shown as slightly shorter than the B30-7, though all published figures I have seen give these models as having the same lengths. I think the illustration was prepared by the simple means of cutting and pasting: two engine-compartment doors were eliminated from the B30-7 drawing to make the B23-7.
    ---#21 of the 58 improvements listed from GEA-10016 is strengthening of the B platform. I wonder if this bit of redesign is connected with the fact that the B23-7and B30-7 tend to be about two feet longer than the U23B and U30B.
    --#4 of the 15 "additional" changes is raising the water header of the 12-cylinder engine to match that of the 16-cylinder engine. I wonder if there is a story here. The 12-cylinder engine was used on many export models, where the whole locomotive has to fit into a smaller loading gauge: I wonder if GE had been using 12-cylinder engines with the "export height" water header on domestic production for simplicity. I have a copy of the 1986-1987 edition of "Jane's World Railways": sections describing the offerings of manufacturers are obviously formatted by the publisher, but the information was provided by the manufacturers, so I'd rank this somewhere close to official GE publications for "horse's mouth"-ness. The GE entry on the FDL engine says that the 8-cylinder version is 86 1/4 inches (2191mm) in height as opposed to the 12 and16 cylinder versions, which are 90 1/8 inches (2289mm) high, but with a footnote on the 12-cylinder version: "Domestic (USA) engines only. The export model has a lower water header (86 1/4 in, 2189mm)".
    ---The final illustration has eight tall engine compartment doors, so probably at leased started as a drawing of a B30-7. (GE obviously wasn't preparing its sales literature with the interests of modellers and rivet-counting rail fans in mind (Grin) !) Interestingly, it is labelled as having slightly SHORTER overall length than the b23-7 shown above: I believe that there were several variations in BXX-7 overall length over the models' production lives, so maybe one change was between the preparation of 3350D and 3350E.

    This is a post I will come back to and reread frequently.

  3. GE may not have used the expression "Dash 7" at the time (I suspect it was coined AFTER they started calling the next generation"Dash 8"), but they have now (January 2014) come around to using it on their website:

    (Though, since they mention only 12-cylinder FDL powered "DASH 7" locomotives, they may now be thinking of it as a designation for part of their export line-- there is something called a C30-7 (or maybe a C30-7i?) which is an updated version of the export U22C and U26C models.)

  4. Another thing that catches my eye: #1 of the 15 additional changes is the replacement of aluminum power cables with copper. Wasn't the use of aluminum cabling one of the things always cited as a defect in the U50C design? (Aluminum cabling can catch fire…) Does this item imply that GE had been using aluminum cabling on lots of other late U-series locomotives?

  5. About #10 on the list of "additional equipment modifications," the radiator cleanout panels. This is a feature visible externally, so...
    Using an online roster of U30C at
    for build-dates, and George Elwood's "Fallen Flags" rail-image site for U30C photos, I checked a number of late(-ish) U30C. I think these bolt-on panels were available as a customer-specified option -- specified ONLY by the Union Pacific -- before the 1976 introduction of the "New Series" models.
    -------All Union Pacific U30C seem to show panels, just below the level of what would become the "wingspan" on the C30-7, in positions corresponding to those on C30-7, which I take to be "radiator cleanout panels": they match those on C30-7 both in size and in position. This includes 2810, the very firstUnion Pacific U30C.
    ------On the other hand, U30C built for other railroads DON'T seem to have these panels. (UP's yellow paint makes it easy to see the panels, but I looked at several photos of U30C of each of the other railroads (except N&W: "Fallen Flags" only has one N&WU30C photo), looking for clear photos of clean units, and I'm pretty sure none of them showed these panels.
    ----------------------This includes CRI&P units (built in late 1973), the last MP U30C (built in early 1974), Louisville & Nashville's 1470-series U30C (built in mid 1972), N&W's sample order (April 1974), and a 1975-built Burlington Northern unit.
    ----------------------Note that the presence of these panels is NOT a mark of the XR series (introduced 1972): Rock Island's U30C have small "XR Series" lettering near the builder's plate, and L&N 1499 was delivered in a special XR Series advertising livery, and neither show radiator cleanout panels.

    Looks like it was a feature that Union Pacific requested -- perhaps they even suggested it to GE -- that GE later decided to include as a standard feature on their next generation of locomotives.

  6. GE introduced AL cable to the railroad industry. It was also used on certain ALCO Century models. The issue was with the cable terminations. They had to made very carefully in order to prevent oxidation-which would result in the connection overheating and creating a possible fire hazard. Even with careful preparation, the connections could (and did) loosen. On U-Series, the cables ran down the left side of the platform underneath the walkway and were accessible for replacement. On the Alco Centuries, the cables ran between the I-beams that made up the the tension members of the underframe. Replacement was a nasty job-as access ports had to be burned into the web of the underframe in in order to un-bolt the cleats that held the cables.

  7. Thanks, David, for the further details! … I think I remember reading, oh, maybe ten years or so back, about a shoreline/regional that wanted to continue using Alco Century types (it may have been the NYS&W with its C-430 fleet), and seeing the remark that a difference of design made re-cabling ahold GE much easier than re-cabling an old Alco.

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