Resistance Due to Starting and Accelerating
Trains face these resistances at stations when they start, accelerate, and decelerate. The values of these resistances are as follows:
Resistance on starting, R6 = 0.15 + 0.005 W2 (25.10)
Resistance due to acceleration, R7 = 0.028aW (25.11)
where W1 is the weight of the locomotive in tonnes, W2 is the weight of the vehicles in tonnes, W is the total weight of the locomotive and vehicle in tonnes, i.e. W1 + W2, and a is the acceleration, which can be calculated by finding the increase in velocity per unit time, i.e., (V2 - V1)/t, where V2 is the final velocity, V1 is the initial velocity, and t is the time taken.
Table 25.1 summarizes the various resistances faced by a train.
Table 25.1 Details of various resistances
|
Nature of resistance |
Value of resistance |
Remarks |
|
Resistance due to friction (Rj) |
0.0016W |
Resistance independent of speed |
Resistance due to wave action |
0.00008 WV |
Resistance dependent on |
|
track irregularities, and speed (R) |
|
speed |
|
Resistance due to wind, or |
0.0000006 WV2 |
Resistance dependent on |
|
atmospheric resistance (R3) |
|
square root of speed |
|
Resistance due to gradient (R4) |
W x % of slope 100 |
Resistance dependent on slope |
|
Curve resistance for BG (R5) |
0.0004WD |
Resistance dependent on degree of curve |
|
Resistance due to starting (R6) |
0.15 Wj + 0.005 W2 |
Resistance dependent on weight |
|
Resistance due to acceleration |
0.028aW |
Resistance dependent on |
|
(R7) |
|
weight and acceleration |
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