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RUNNING TIME BETWEEN SIDINGS.

It has long been

recognized that one method of increasing the capacity of a railroad line is to reduce the running time between sidings. Running time between sidings can be reduced by two basic adjustments: 1) increasing the operating speeds of trains and, 2) reducing the distance between sidings. The basic formula used to estimate line capacity based on running time between sidings is:

C =
T
t

Where C equals capacity expressed in terms of the number of trains operated daily, T equals the number of minutes per 24 hours the line segment is available for use, and t equals the estimated running time between sidings giving consideration for the time required for starting and stopping the train. If the one way capacity is required, the formula

can be adjusted as follows:

C= ÷

The impact the running time between sidings can have on line capacity is illustrated in Table 6. For example, if the running time between sidings is 60 minutes, the estimated line capacity would be only 24 trains daily (1440 → 60 = 24). If the running time between sidings is reduced to 20 minutes, the line capacity would be increased to 72 trains daily (1440+ 20 = 72).

As indicated earlier, two basic approaches can be used to reduce running time between sidings. The impact of reduced distances between sidings on capacity are shown in Tables 7, 8, and 9. A similar illustration concerning train speeds is shown in Table 14.

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TABLE 7

IMPACT OF DISTANCE BETWEEN SIDINGS ON LINE CAPACITY

Average Train Speed 10 MPH
Line Available 24 Hours Daily