GP50 - MagnumMacKivler/RLCPT2 GitHub Wiki
An early GP50 locomotive for the Frisco railroad sits in Memphis, TN in 1981. Photo credit Lon Coone and the Frisco Archive
The GP50 locomotive is the four axle version of the infamous "50" series. Along with it's 6 axle cousin, the SD50, it featured a higher RPM version of the 645 prime mover with a new turbocharger, known as the 645F. The GP50 also featured a standard anti-climber on the front from the 88" nose, but not much else changed with the car body from the GP40-2.
GP50 locomotives seemed to fair better on railroads better than their 6 axle cousins, however they too fell from reliability problems from the already stressed 645 engine. From rushed horsepower development pressure from General Electric, to modifying the engine block to run 54 more RPM with higher pressures and temperatures not originally anticipated, the 645F was notorious for failures. A boost to 3600 horsepower caused more mechanical headaches, and eventually most (if not all) GP50s were either reduced in horsepower output to reduce mechanical stresses, or totally rebuilt with new prime movers. Some intact GP50s survive, however (on railroads such as the Austin Western with their fleet of ex CNW units as of 05/2019)
Burlington Northern in particular ordered 5 elongated-cab locomotives. This new cab type variant, called the GP50L (for long) was made to accommodate union requirements of 5 man crews in anticipation of plans to put cabooses out of service. No 5 man crew was ever assigned, and thus the cabs were no longer needed.
GP50 locomotives were produced from 1980 to 1985, with 278 units being produced. The GP50 was superseded by the GP60 in 1985.
A Burlington Northern GP50L, one of only 5, had its photo taken likely as a builder photo. Author unknown
PT-Specific Information
| General Info | - |
|---|---|
| Prime Mover | 16-645F3B |
| Horsepower | 3500 HP (1) |
| Truck Type | EMD "Blomberg" M, HTB (2) |
| Axles | 4 |
| Traction Motors | 4 |
| Minimum Weight | 260,000 lbs |
| Maximum Weight | 280,000 lbs ⚠ |
| Model Base Speed | 70 MPH |
| Top Speed | 70, 76, 82 or 88 MPH |
| Electrical System | - |
|---|---|
| Generator Max Current | 6600 amps |
| Max Traction Motor (TM) Current | 1650 amps |
| Max Continuous TM Current | 1170 amps |
| Traction Motor Type | DC |
| Factor of Adhesion | 25%, 27%(2) ⚠ |
| Transition Mode | Automatic |
| Transition Groups | 1 |
| Transition Shunts | 1 |
| Generator Transition | Yes |
| Traction Control | APR with sanding |
| Dynamic Braking (DB) Mode (if used) | Mechanical Blowers |
| DB Max Current | 700 |
| DB Max Continuous Current | 700 |
| Blended Braking | No |
| Miscellaneous | - |
|---|---|
| Head-End Power (HEP) | No |
| HEP Power Consumption | N/A |
| HEP Standby/Run Mode | N/A |
| Load Ramp Speed | 2 Amps/Tick |
| TM Overload Protection | No |
| Starter Mode | Manual Primer, Manual Start |
| Air Brake Schedule | 26L |
| Compressor CFM | 269.2 (WBO @ 954 RPM) |
| Main Reservoir Volume | 35 Cubic Feet |
###Notes:
(1): Late GP50s were bumped up to 3600 horsepower
(2): The HTB was offered for GP50 but was never purchased by any railroad; HTBs Factor of Adhesion is guesstimated to be 27%
⚠: Not verified or educated guess