EMD GP50

An EMD GP50 is a 4-axle

EMD delivered the first GP50s to Chicago Northwestern in the summer of 1980.^[1] Much of the GP50's new technology was tested and developed with the experimental GP40X.^[1]

Changes to the 645F3B 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 AR15 alternator rated at 4,680 amps.^[1]

The GP50 was the first production locomotive to feature EMD's Super Series wheelslip control system, first seen on the GP40X. Super Series employs a Doppler 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 the GP40-2 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 a microprocessor, and EMD fitted the 60 series with microprocessors as standard following the success of LARS which was developed in partnership with Burlington Northern and Rockwell Collins.^{[citation needed]}

Original Owners

Image	Railroad	Quantity	Road numbers	Notes
	Atchison, Topeka and Santa Fe Railway	45	3810-3854	All now in service with BNSF Railway. 3853 wrecked and retired.
	Burlington Northern Railroad	63	3100-3162	3100-3109 were ordered by St. Louis – San Francisco Railway, but delivered to BN. 3100 was the only one that received Frisco colors, though with BN number. LARS was installed on 3108-3157. Most are now in service with BNSF Railway and some are being rebuilt as GP25s .
	Chicago and North Western Railway	50	5050-5099	To Union Pacific Railroad; since retired.
	Missouri Pacific Railroad	30	3500-3529	To Union Pacific Railroad.
	Southern Railway	90	7003-7092	These were built with High Hoods for GP33ECOs .
Totals		278

Rebuilds

Norfolk Southern

In 2015–2016 the

GP33ECO.^[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.

Burlington Northern Santa Fe

Around 2006 BNSF started rebuilding and derating GP50s and reclassifying them as GP25s.^{[citation needed]} These locomotives are regoverned to 2500 hp and have D78 traction motors in place of the original D87s. This likely means that the Super Series wheelslip control system has also been removed since the D78 traction motor does not support it.^{[citation needed]}

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Peek, Dr. David F. (November–December 1980). "CNW EMD GP-50". Mainline Modeler.
^ "NS unveils first publicly funded GP33ECO locomotives". Trains. January 6, 2015. Retrieved 12 January 2015. (subscription required)

External links

Sarberenyi, Robert. EMD GP39X, GP49, and GP50 Original Owners

[Peek1-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h Peek, Dr. David F. (November–December 1980). "CNW EMD GP-50". Mainline Modeler.

[trn20150106-2] "NS unveils first publicly funded GP33ECO locomotives". Trains. January 6, 2015. Retrieved 12 January 2015. (subscription required)

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