The GE (General Electric) "Super 7" Series is a name that originally described a line or series (primarily a sub-series or sub-line)
GE B23-S7

A Monongahela B23-S7 or B23-7R. MGA #2303 is one of 11 units built for the Pennsylvania-based shortline. Riding on EMD Blomberg trucks from traded-in "Geeps" and a U23B frame, #2303 awaits its next assignment sometime in the early 1990's prior to the Conrail merger.

of four-axle and six-axle diesel locomotives which began as the prototypical name for the Dash 8 line testbeds from 1983 to 1987, and eventually became part of a rebuilding program from around 1989 to 1994 which primarily served as a service plan for upgrading and rebuilding aging Universal Series ("U-boats") models owned by various Mexican and other Latin American railroads and/or railways.

The line itself, was (and often at times is) often considered to be part of the Dash 7 series or line because of the obvious name. The trademark name for the locomotive line is also very reminiscent of the EMD SD40X: a class name which served as the name of the original SD40 testbeds, but eventually became the name of the subsequent SD50 testbeds. It's obscurity also dates back to the "SD50A" and "SD50AF": the prototypical model designations for what would become the EMD SD60 and SD60F.

Many still exist, but are exceptionally rare in the United States and Canada as opposed to Mexico and the rest of the Latin American region, where they are usually a common sight for various carriers whom own such units: such as FXE and KCSM. Although the Super 7 line was offered to numerous American and Canadian carriers, none grew particularly interested except for two shortlines: Monongahela (MGA) and Roberval and Saguenay (RS) of Canada, who ordered 17 (2 for RS, the remainder for MGA) of the only four-axle B23-S7 (or B23-7R; "R" for "rebuild") units built. Though, several have since been acquired following the Conrail split of 1999 (several years after the MGA-CR merger of 1993) and still survive on various other shortlines (primarily on the Providence And Worcester Railroad; a predominantly GE-based carrier).

Only a handful of former Monongahela (MGA) B23-7R rebuilds can still be seen on various shortlines (such as the P&W and Ohio Central), while three are currently in service with CSX.


The Super 7 Series line originally served as a basis for the Dash 8 line or series of diesel locomotives (primarily the actual name, though the unofficial name for the early Dash 8 units was known by said obscure trademark); having high-tech microprocessor technology, updated traction motors, alternators, and high-tech cooling systems which were originally inspired from EMD's "Tunnel Motor" design from said series. Though, the "Tunnel Motor" series and "Super 7" series are alike in many ways; especially considering that the latter locomotive models in both lines included rebuilds; being the EMD GP15-1 and GP15AC as opposed to the SD40T-2 and SD45T-2). What was known as the "Select-A-Power" agreement through Conrail's partnership in development for the C32-8 became apparent that a new locomotive line was underway, proving that "Super 7" was simply a beta name. Another example would be GECX #505, a C36-7 retrofitted with Dash 8-style features (including dynamic brakes and microproccessor control modules), marking the transition between the two locomotive lines.

The original "Super 7" name designation given to early Dash 8 units was named so because of the overall design of the earlier units being reminiscent of the preceeding "Dash 7" series or line. The original Super 7 project, in-turn, was short-lived (obviously due to the rapid development of the actual Dash 8 line), and eventually became part of a rebuilding program (as listed).

The previous line itself, was also vaguely similar to GE's "XR Series" U-boats which in-turn served as the basis for GE's early stages of the Dash 7 line, therefore utilizing a similar concept.


The "redeveloped" Super 7 Series line initially served as a rebuilding program for Mexican railways to rebuild and add a new service plan to replace, improve, and extend the lives of numerous tired Universal Series diesels to Dash 7 standards or specifications. At the time of the line's introduction, various companies who owned numerous fleets of said aged U-Boat units were offered a chance to extend their warranties and agreements with GE. Although the Dash 7 units owned by such carriers were reliable, their warranties weren't guarenteed to last, for the locomotives were deemed to become no longer reliable after quite some time as a result of being "conventional power"; meaning that they weren't guarenteed to last nearly as long as their initial competitors (such as EMD) but to rather serve as "conventional power" to serve railroads with locomotives which would "get the job done" at any rate with no hassle.
TFM C32-S7

A TFM C30-S7N or C32-S7 (often classified with having 3,200hp).

Though, considering Mexico's long-troubled economic issues, railways such as N de M (before becoming redeveloped as Ferromex under government economic reform) were in severe financial debt, and simply couldn't afford to purchase new engines or units to replace their so-called "aged" fleets of GE diesels.

Thus, the "Super 7" line was coined: this time as a motive to give Mexican consumers a chance to experience the same advanced microprocessor technology implimented with American Dash 8 diesels, only combined with older, more traditional technology for the employees who were more familiar with traditional diesels like the SD40-2, which basically gave the rebuilds "new faces on old bodies", or a new look for an old vehicle (and by further giving GE more foreign consumer opportunities). Earlier units weren't fitted with the luxury of Dash 8 microprocessors, but were given a basic on-board computer package. Such features included microprocessor-managed thermal protection and Sentry adhesion control. It wasn't until the production of the 34 microprocessor-equipped C30-7MP units when the line became on-par with the domestic Dash 8 line.

During the early-1990's prior to the UP (Union Pacific) merger or acquisition in 1995, the Chicago And Northwestern (CNW) utilized several C30-S7 demonstrators alongside their existing C40-8 units in standard revenue service for performance comparison. Considering that the railroad; for the longest time, was solely an all-EMD customer, GE began to convince the CNW to purchase more of their products "by the dozen" by promoting their ever-increasing success with the newly-redeveloped "Super 7" line, futher making an attempt at attracting remanufactured locomotives to the carrier by succeeding where EMD failed with the less-favorable GP15 line. Although the demonstrations were successful, the railroad lost interest in purchasing second-hand rebuilds like the C30-S7 in favor of their new, collaborative Dash 9 and later AC-traction AC4400CW models. Though, the imminent CNW-UP merger also prevented further interest for the railroad's acquisition of Super 7 diesels.

Many of the export and foreign-built models still exist and are in active service on most Mexican and South American railways, but are slowly in the process of becoming updated (as a result of having now-outdated technology), scrapped, or retired.

Characteristics and ConfusionEdit

The main ways of identifying original pre-Dash 8 units and rebuild Super 7 "N", "MP" and "R" designated units is by their overall appearance. Such distinguishing characteristics would be:

  • Rounded-cab (often nicknamed "hump-back" or "hunch-back" by most railfans) - can be seen on the C32-8, C39-8, the C39-9 demonstrator, and the three B32-8 prototypes
  • Slanted-cab (also known as a "spartan-cab" or "wedged-cab") - can only be seen on rebuilt units or initial production Dash 8 units (such as the C40-8)
  • Carbody-style - most "R" units have a flat, yet slightly slanted upper carbody where the dynamic brake or turbocharger section is located, while "N" and "MP" units have either flat upper carbodies or those built similar to Dash 8 units
  • Hood (or "nose") - most "MP" and "N" units have larger hoods than other average Dash 8 and Super 7 units
  • Radiator fins - vary in size; primarily length, width, and height

Like with every other type of diesel locomotive produced by GE, each locomotive in the series or line is designated by their horsepower rating (as a two-digit number), axle classification, or specialty. Thus, giving each model its own respective name. Such as:

Example: C44-9W.

  • The "C" meaning, "C-C" or "Co-Co" in UIC or AAR axle classifications
  • The "44" meaning, "4,400hp" (horsepower)
  • The "-9" meaning, "Dash 9" (obviously referring to the name of the actual series or line)
  • The "W" meaning, "wide-cab" (being a special designation)

Hence: B23-7R

  • The "B" meaning, "B-B" or "Bo-Bo" in UIC or AAR axle classifications
  • The "23" meaning, "2,300hp" (horsepower)
  • The "-7" meaning, "Dash 7" (referring to the name of the actual series or line, but in this case the "R" after the "-7" or "S" before such better describes the status of the model)
  • The "R" meaning, "rebuild/rebuilt"
  • The "S" meaning, "super"
  • The "R" initial designation actually stands for "rebuilt" or "rebuild".
  • The "MP" initials stand for "microprocessor"; these units were actually built in Brazil and Mexico as opposed to GE's main locomotive facility in Erie, Pennsylvania.
  • The "N" initial or designation often stands for "newly-cast frame"; having a thicker frame for additional support while also being mostly remanufactured or replaced from the original base frame from retired "U-Boats".

Although many existing B23-7 diesels have since been rebuild and given a "B23-7R" designation, its Super 7 counter-part is often commonly referred to as a "B23-S7" to avoid confusion.


Pre-Dash 8 (testbed era):Edit

B32-S7 (B32-8)

B36-S7 (B36-8)

B39-S7 (B39-8)

C32-S7 (C32-8)
GE Super 7

A six-axle C30-S7 "Super 7" demonstrator (which is actually kitbashed and rebuilt from models such as a U33C or U36C, as well as a C30-7 in some cases) seen on the CNW in the early-1990's.

C36-S7 (C36-8)

C39-S7 (C39-8)

Post-Dash 8 (Dash 8 production/debut era):Edit


C30-S7 (often designated as a "C30-S7R")




ALCO "Century Series" and earlier predecessor GE "Universal Series" (U-Boat) diesel locomotives owned by GECX (General Electric Corporation Leasing) in Erie originally served as some of the other prototypes for the initial "Super 7" rebuild line; besides the already-developed Dash 8 line.

CSX acquired only 4 ex Conrail (nee Monongahela) B23-7R (B23-S7) units during the Conrail split of 1999. Such units are often rated at 2,000hp as opposed to originally having 2,300hp.

The Arkansas And Oklahoma (AOK) shortline acquired two former NS (originally MGA, but then inherited through Conrail during the 1992-1993 merger) B23-S7 units from NS in 2001, and have remained in active service ever since. Said units are actually rebuilt from Western Pacific (WP) U23B ancestry.

GECX #2000 was the number given to a B23-7R before it was sold to the Providence And Worcester as PW #2215. Many of the Super 7 units built for FNM (N de M) were actually built on the frames of a cancelled back-order of B23-7 units. Said frames sat dormant in the backlot of GE's Erie facility for several years before finally having found use after the initial discontinuation of the Dash 7 line.