Often it was just politics and advertising up until about 1950.
At that point in time some trains were traveling fast enough (say quicker than 50 or 60 mph) so that air resistance became a significant retarding factor.
Long time ago, animals pull the trains till they are tired
Bullet trains are conventional electric trains, named bullet trains due to their streamlining. They use conventional railroad tracks and electric catenary systems, but built and maintained to very tight tolerances.
Diesel trains are used for freight and sometimes they're used for passenger trains.
to reduce air resistance or drag.
Passenger trains are used to transport passengers.
steam engine trains.
Coal is still used in many steam engines today. Coal is not used on diesel trains or electric trains simply because it is not fuel for them. Electric trains and diesel trains are the most common trains in use, and not trains capable of using coal, because they are more efficent and much less costly to maintain.
Japanese Trains
it is used to help athletes improve their performances
What type of coal do they use in trains?
why commuters don't used the trains
The expression "the father of ...." usually refers to someone who brought the thing referred to to public prominence, or who influenced the study or practice of it more than anyone else. So, the Father of streamlining would most likely refer to an engineer who brought streamlining to perfection in his designs for vehicles... be they cars, trains or airplanes.