Traction Mechanics
Traction Mechanics is the study of train motion.
The mechanics involve converting overhead electrical /diesel/steam power in rail horsepower to haul a train encountering acceleration, train, grade, curve resistance, and similar braking.
Traction Mechanics involves the concept of
- train resistance
- tractive effort
- braking effort
- adhesion
- balancing speed
for detailing the motion of a train.
Units
The units followed in the day-to-day talk of Railways are different from the conventional MKS systems. The conversion table is given below for a better understanding
Item | Symbol | Railway convention | MKS |
Time | t | Hours | 3600 sec |
Distance | D | Kilometer | 1000 meters |
Speed | V | Kmph | 1000/3600=0.277m/sec |
Acceleration | fa | Kmph/sec | 0.277m/sec/sec |
Weight | W | Tonne | 1000Kg |
Force | F | Kgf | 9.8 Newton |
Energy/Work | kWh | kWh | W-sec or N-m or Joules |
Formulas
where D-distance;V-final speed; U-initial speed; a-acceleration
where W in N-m or Joules or Watt-sec)
where TE is in Kgf, V in Kmph and HP=75*Kgf*m/sec
where η is efficiency of Loco
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