Electrical Engineering ⇒ Topic : Speed-time curve

SPEED-TIME CURVES FOR TRAIN MOVEMENT

The actual run of a car or train can graphically be represented by a speed-time curve which consists of the following:

• Acceleration
• Constant speed or free running
  
• Coasting, where power is shut off and the retardation, is produced by resistance to motion
• Retardation due to braking.

                                                       Figure (a) Speed-time curve

Electric Traction

A typical speed-time curve is shown in Figure (a)

Crest speedThe maximum speed attained by the vehicle during the run is known as crest speed

Average speedThe mean of the speed from start to stop, i.e., the distance covered between two stops divided by the actual time of run is known as average speed. o

Schedule speedThe ratio of distance covered between two stops and total time of run including time of stop is known as schedule speed