When an extra receives orders to run over working limits it must be advised that the work train is within those limits by adding to example (a) the words:
(g.) Eng. 202 is working as an extra between Berne and Turin.
A train receiving this order must run expecting to find the work train within the limits named.
Under Form H it has been undertaken to cover the whole subject of orders for extra trains, excepting for cases which come naturally under other forms, as when an extra is ordered to meet another train.
The term "wild" has been quite extensively used for these trains, and history should preserve the fact that on some roads, when a train was ordered to run extra, it was directed to "wildcat."
An order for a train to run extra is very simple. The train is accurately designated by the number or name of its engine, and the order reading as in example (a) is the foundation for those which follow.
This is of course not a duplicate order. But one train is concerned, and there is no other train to be notified until it becomes necessary to forward the extra by meeting or other orders. In those it is described as an extra and treated as any other train, but in the meantime it must keep out of the way of all regular trains, and the Dispatcher must keep it in hand and especially guard against having more than one extra on the same part of the track at the same time. Here is an element of danger where the necessities require frequent extra trains. Whenever practicable, trains should be run on a regular schedule, but it will often happen that there is no regular train upon which signals may be carried for a train that must be run, and it must go as an extra.
A precaution which has been found valuable is for the Dispatcher to have before him a large blackboard on which he shall place conspicuously the number of each extra ordered. The habit, soon acquired, of looking at this whenever an extra is ordered, has proved a sufficient safeguard where this plan has been used.
There is a class of extras which cannot be dispensed with, and the management of which gives rise to serious difficulty. These are the material or "work" trains. These trains must work upon the track away from stations, often with a large force of men, and delays to their operations cause expense as well as hindrance to work. At the same time they must not be permitted to interfere with the passage of regular trains, nor of others more than can be avoided. The solving of this problem has been attempted in various ways. Some allow the "work train" to occupy the track by right, except that it must keep out of the way of regular trains. Some permit it to work under flag "until freight trains come in sight." To get it out of the way for any but regular trains, the want must be anticipated, and an order given while it is within reach for the work train to report for orders at a designated hour and place. This plan does not give as complete control of the movements of the work train as is desirable.