HT-C truck

The HT-C truck was created in 1970 by Electro-Motive Diesel (EMD) as a component of their range of railway locomotives through to 1994. It was mounted under the experimental EMD SD45X, and applied to a majority of Dash 2, 50 and 60 series six axle units built by EMD. It has a total of two brake cylinders on the end axles and a shock absorber on the middle one and has a tail on the fuel tank side to hold the #3 and #4 motors in line with the #2 and #5 motor, unlike the Flexicoil truck which these two face the #2 and #5 motor under the engine

When Amtrak bought their EMD SDP40F's from 1972 to 1974, they specified this truck to be fitted with hollow bolsters to mount the engine on the trucks with a lighter load rating to offset the weight of the secondary water tank that was mounted in front of the steam generators. This contributed to the yawing effect that was characteristic of the second SDP in the consist and the baggage car. The result was the fact that the unit and the car pulled the outside rail out from under the train on high speed curves. Burlington Northern, Chessie System, and Louisville & Nashville banned the SDP's because of the modified truck. Conrail ordered their EMD SD40-2's and their early EMD SD50's with the older Flexicoil trucks because of the HT-C issues with BN, Chessie and L&N. The Federal Railroad Administration and Electro-Motive determined that the baggage car was to blame.

This did not doom the truck as it did to the SDP40F. They went under almost every EMD six axle locomotive built from 1972 to 1994 except the Detroit Edison SD40's, Conrail SD40-2's, Milwaukee Road SDL39's, EMD/BN/Siemens AG SD60MAC, and the EMD SD70 series.