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AnEMD GP50 is a 4-axlediesel–electriclocomotive built byGeneral Motors Electro-Motive Division (EMD). It is powered by a 16-cylinderEMD 645F3B diesel engine, which can produce between 3,500 and 3,600 hp (2,610 and 2,685 kW). 278 examples of this locomotive were built by EMD between 1980 and 1985. BN 3110-3162 were all delivered with five cab seats, the final five of these having the cab lengthened 23 in (584 mm) vs. the standard EMD cab. The GP50 retains the same overall length of 59 feet 2 inches (18.03 meters) as theGP38,GP39, andGP40 series locomotives.
EMD delivered the first GP50s toChicago and North Western in the summer of 1980.[1] Much of the GP50's new technology was tested and developed with the experimentalGP40X.[1]
Changes to the645F3B engine compared to older versions, include a stronger crankcase, new turbocharger, new plate crab for clamping the power assemblies to the crankshaft, a camshaft of increased hardness, one-half-inch-diameter plunger injectors, laser-hardened cylinder liners, rocking piston pins, and a slower idle speed.[1] A new traction motor, the D87, has a continuous rating of 1170 amps, compared to 1150 amps for its predecessor, the D77, with new interpole and main field coils that use 16% more copper, the number of turns increased from 14 to 17 to improve commutation at high currents, longer brush life, and sturdier gearing with increased surface hardness.[1] The new motors are connected in permanent parallel to a new AR15alternator rated at 4,680 amps.[1]
The GP50 was the first production locomotive to feature EMD's Super Serieswheelslip control system, first seen on theGP40X. Super Series employs aDoppler radar unit mounted under the front coupler pocket to measure the locomotive's speed[1] and adjusts the power to each axle to provide maximum adhesion while eliminating wheelslip. This system provided an increase in adhesion of at least 33% compared to conventional locomotives.[1]
Other changes compared to theGP40-2 include an underframe with a lighter, deeper sill that reduced the frame's weight and a new exhaust system and "Q-type" cooling fans to meet January 1980 Federal noise regulations.[1]
The GP50 was the first production locomotive series to be fitted with amicroprocessor, and EMD fitted the60 series with microprocessors as standard following the success of LARS which was developed in partnership withBurlington Northern andRockwell Collins.[citation needed]
| Image | Railroad | Quantity | Road numbers | Notes |
|---|---|---|---|---|
_(10582673124).jpg) | Atchison, Topeka and Santa Fe Railway | 45 | 3810-3854 | All now in service withBNSF Railway. 3853 wrecked and retired. |
.jpg) | Burlington Northern Railroad | 63 | 3100-3162 | 3100-3109 were ordered bySt. Louis – San Francisco Railway, but delivered to BN. 3100 was the only one that received Frisco colors, though withBN number.LARS was installed on 3108-3157. Most are now in service withBNSF Railway and some are being rebuilt asGP25s. |
_(10570575516).jpg) | Chicago and North Western Railway | 50 | 5050-5099 | ToUnion Pacific Railroad; since retired. |
_(10568775276).jpg) | Missouri Pacific Railroad | 30 | 3500-3529 | ToUnion Pacific Railroad. |
_(16411959476).png) | Southern Railway | 90 | 7003-7092 | These were built with High Hoods forSouthern.Norfolk Southern has rebuilt 28 of theirGP50s asGP33ECOs. |
| Totals | 278 |
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In 2015–2016 theNorfolk Southern Railway rebuilt 28 of their GP50s into the low-emissionGP33ECO.[2] And in early 2016, Norfolk Southern rebuilt one GP50 into their first GP59ECO. These units, most of which utilized GP59 cores, have similar specifications as the earlier GP33ECO program but have been built without public funding contributing to their construction.
In 2004,BNSF started rebuilding and derating GP50s and reclassifying them as GP25s.[3] These locomotives are regoverned to 2,500 hp (1,864 kW) using new load control systems (LCS).[3] The original D87 traction motors may have also been replaced by D78 traction motors, since the original traction motors would not have supported this rebuild. Many of these GP25s have been put to use asremote control locomotives.[3]
