:I'm glad somebody has investigated rolling friction vs . aerial drag-I recently got into a heated debate about which was the more relevant engineering challenge ( I think I was wrong, in light of SteveBaker's numbers : ) Nimur 19 : 25, 18 February 2007 ( UTC)
32.
In order to start a train and accelerate it to a given speed, the locomotive ( s ) must develop sufficient tractive force to overcome the train's drag ( resistance to motion ), which is a combination of inertia, axle truck ( bogie ) hunting, which will increase the rolling friction between wheels and rails.
33.
So the locomotive should pull the front car, second car, third car etc . all with the maximum length of the connector, until either the train is moving slowly or else it is totally stopped because the coefficient of static friction on the last car, plus the coefficient of rolling friction on the cars already moving, is enough to totally counter the front locomotive's pull.
