Good morning all.
If a railroad is transporting one or more diesel locomotives dead in tow,is the power needed calculated by the actual tonnage or is more added on for the drag of the the motors and gearing? would the motor drag be negligible?
Good day. [:D]
Lee
Lee,
Motor /gearing drag is really not an issue. If the unit is geared for lower speed, a speed restriction may be placed on the train so that the windings in the traction motors will not be damaged. Most traction motors have a maximum rotational speed that should not be exceeded. Even if the unit is not under power, rotating the traction motors will result in a Back-EMF being generated.
Jim
Typically neither unless they are moving a LOT of dead engines. Moving one DIT engine, the power needed is so small compared to the thousands of tons of the train that has to be moved.
Guys
I didn’t phrase that question correctly. I was thinking of a train headed someplace with 3 or 4 dead locos sent back for repair or reposition. If they are dead weight wouldn’t you count them like a car or two when the train is made up?
Have a good day. [swg]
Lee
Sounds like your typical Southern Pacific train in the late 80’s and early 90’s! =P
Lee,
They will count on the tonnage. A typical 6 motor engine is 200-210 tons, and a typical 4 motor engine is about 130 tons. The engineer’s brake control valve will be cut out and the engine will be-have like a normal freight car.
Jim
Typically no, though you could. Normally the dead engines fall into the rounding off the tonnage and horsepower. Its not an exact science.