Computer Aided MBS

CP Rail has been making great progress in the computerization of its Manual Block System (MBS). In recent years train movements have been improved by the use of MBS which is a way of issuing train movement instructions by the dispatcher directly to train crews.  The key to this system is complete radio coverage which allows the dispatcher to contact trains at any time.

The main weakness of MBS when first introduced was that a great deal of responsibility was placed upon the dispatcher to ensure that he did not issue overlapping authorities and it was this that caused CP Rail to look at computer assistance. This has now progressed to a fully functioning system. The dispatcher has two CRT displays, one in colour and one monochrome.  The colour display allows him to select the subdivision and review the clearances that he has issued.  These are shown along a representation of the timetable with the stations and mileages shown down the middle.  Clearances are shown in different colours, (green for a regular train holding the main, yellow for a train taking the siding, red for a work train, etc). The monochrome screen shows information concerning the trains and their crews and allows the dispatcher to read over the permits as he issues them.

The computer will not allow the dispatcher to issue overlapping orders. In fact, much of the rule book is built into the system so that the computer acts as a check against the rues.

Train crews and dispatchers seem to like the system, which has been implemented throughout most of the CP Rail network, the main exception being in Quebec which will take another six months because of the need to build into the computer the ability to repeat clearances in French as well as in English. By the middle of this year there may well be no timetable and train order territory on CP Rail. If you have any pictures of people hooping up orders hold on to them as they are a thing of the past.

What is the next step? It is to ensure that locomotives do not exceed the author­ities granted them. As a first step there will be some form of a display on the locomotive giving the engineman a visual indication of his authority. The next stage will be to build this into a distance travelled counter that will sense when the locomotive is about to exceed its authority and take action to ensure that the engineman does not do so. CP Rail is already testing a switch in the Red Deer, Alberta, area which can be thrown by radio from the locomotive several miles away. Once the engineman has thrown the switch he retains complete control over it until he passes over it.

You may not realise it but the railway is rapidly moving into the computer age insofar as train control is concerned. This will happen quickly. Watch for these exciting developments to take place in the experimental stages, at least later this year.


Bytown Railway Society, Branchline, March 1987.

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