What size of locomotive engine (Diesel-electric) would I need for 100cars carrying 50tons each with 0.5% grade

Question

What size of locomotive engine (Diesel-electric) would I need for 100cars carrying 50tons each with 0.5% grade

Answer 1

You would need something like four SD80MAC class engines, or four Dash 9s.  You could put all four up front or put three up front and one in the rear for dpu.

Kent in SD

Answer 2

With that kind of tonnage as Kent said, you would likely need a more powerful locomotive model like the SD70MAC, SD80MAC or GE-built C44-9W or ES44AC (the successor model to the C44-9W).  Note that all of the units we mentioned carry AC current instead of DC, the reason being that AC is much much better at pulling heavy tonnage over moderate/steep grades.

Answer 3

As speed decreases, amperage to the traction motors increases.  At speeds around 12 MPH or less, at full throttle, will result in the traction motors going into "short time" rating, which varies slightly from model to model.

When in short time, ratings must be observed.  They are expressed as a simple amperage/time ratio.  If at the maximum, you will be looking at no more than 5 minutes of running before a stop must be made to allow the traction motors to cool.  Failing to do so will either burn the motors or melt electrical supply cables.

Knowing what speed we want to maintain, the next step is to apply a simple formula called the "rolling train resistance formula."  It is as follows:

Horsepower per ton, times 12, divided by the per cent of grade will equal speed, or HPT x 12 / %G = Speed.

Determine what speed you want to make, then apply the formula inverted to determine horsepower needs.