April 20, 1953 Railway Age Vol. 134 No. 16

Oba Subdivision, equipped with C.T.C., is about half way between Montréal and Winnipeg.

On the Canadian National

C.T.C. for 12 Trains Daily

Train operations in light-traffic territory by signal indication based on siding-to-siding block, employing power switch at one end of sidings and spring switch at the other, without intermediate signals.

On a single-track, 148-mile subdivision which has 10 to 12 scheduled trains daily, the Canadian National has installed a centralized traffic control system in which the costs of the project were reduced in proportion to the traffic.

This installation has a power switch at one end of each siding and a spring switch at the other. Overall blocks extend from siding to siding, with no provision for following moves in such a block. This arrangement saved the expense of intermediate signals, and a a result, for a cost not too much more than for complete conventional automatic block, the Canadian National has attained the important objective of train operation by signal indication, as well as avoiding a very high percentage of train stops when entering and leaving sidings.

Location of signaling

This new signaling is between Foleyet, Ont., and Hornepayne, on the Oba subdivision. which is part of the Canadian National transcontinental route from Halifax on the Atlantic lo Vancouver on the Pacific, As show on the map, lines from Montréal and Toronto join at Capreol. From Capreol, the line extends west, and slightly north, through the territory north of Lake Superior, Oba being about 200 miles directly north of Sault Ste. Marie. In general, the railroad follows the natural divide between the Great Lakes and the Hudson Bay region.

This Oba subdivision lies in typical North Woods country, mostly wooded with spruce, pine, poplar and cedars. There. is no farming or industry in this territory except for a limited amount of 1umbering and pulp wood cutting.

Grades and curvatures

Between Foleyet and Agate, 38 miles, there are numerous curves ranging up to 6 deg. The ruling grade eastbound varies from 0.2 to 0.4 per cent for about 9.3 miles east of Elsas. Between Agate and Hornepayne, 110 miles, the grades and curvature are light. Maximum permissible speeds are 60 m.p.h. for passenger trains and 50 m.p.h. for Freights. Speed reductions to 40 m.p.h. are in effect at six locations, to 45 m.p.h. at one and to 50 m.p.h. at six locations.

The Algoma Central & Hudson Bay crosses the Canadian National at 0ba, 109 miles west of Foleyet. At Oba there are two sidings, of 89 and 92-car capacity, one siding for passenger train meets, and a small interchange yard.

Trains stop for fuel and water, and for inspection, at Fire River; where there is an extra long siding. Single sidings at 15 other places range in capacity from 77 to 82 cars. At one end of each of these sidings there is a short set-off track to hold bad-order cars or camp cars used by track gang.

Why the Oba segment was signaled first

Previously, there was no signaling anywhere in the entire 1,033 miles between Capreol and Winnipeg. The Oba subdivision was chosen to be signaled first because the line's three eastbound passenger trains are scheduled to meet the corresponding three westbound passenger trains within its limits every afternoon. Also, fast merchandise freight trains between Montréal or Toronto and Winnipeg are scheduled to meet on this subdivision. The number of trains varies from an early morning low to a mid-afternoon peak, during which for a few hours operations are at the rate of practically 60 trains a day, although the actual total for the 24 hours may range from a low of 10 trains to about 16, with infrequent peaks of 18 or 20.

Three passenger trains are operated each way daily in the summer, July 1 to October 1, and two each way are operated daily in the remainder of the year. Six manifest freight trains are scheduled daily. Freight traffic, such as merchandise and manufactured products, varies from a low on Monday and Tuesday to a high on the weekends. During the winter, after navigation closes on the lakes, about four trains of loaded grain cars are handled eastward daily from about December 1 to April 1.

Difficulties in getting operators

Because of the isolated locations of offices, it was difficult to secure enough good operators for the Oba subdivision. The dispatcher had to work with information from eight day operators and five night operators, or in the peak period of the day roughly from every other one of the 17 sidings. Each open office held a 20-minute time block behind each passenger train. During winter, trains were operated on absolute block which required 13 extra operators. To get trains over the subdivision in reasonable time exceeded the capabilities of the train order system.

Freight trains commonly took nine or ten hours, even more, between Hornepayne and Foleyet, an effective speed of about 15 m.p.h. Some freights were unable to depart from Foleyet or Hornepayne when ready in the late forenoon and early afternoon, because passenger train time was near. Delays were so serious that they adversely affected the overall east-west performance of the railway.

Signals govern train movements, the blocks extending from siding to siding.

The Canadian National for several years has had complete C.T.C. in service on two subdivisions with heavier traffic; one from a point near Montréal to Lévis (Québec), and a second from Moncton, N.B., to Halifax, N.S. Based on the excellent results in these territories; it appeared logical to install C.T.C. on the Oba subdivision.

With total traffic at times as low as 10 trains daily, however, it was desirable to install, at first, something less than full C.T.C. in order to reduce the cost somewhat in proportion to the volume of traffic. This was particularly important because it was recognized that similar signaling is needed on the entire 1,083-mile Capreol-Winnipeg link between Eastern and Western Canada, for which reason funds available for signaling had to he spread as thin as was consistent with safety and train operation by signal indication.

Switch and signal arrangement

The typical arrangement of signals and switches, in this modified C.T.C.; is illustrated. A power switch is installed at one end of each siding, and a spring switch at the other. At each power switch there is a standard arrangement of signals to direct trains either to (1) continue on the main track; (2) enter the siding; (3) leave the siding; or (4) stop. At the spring-switch end; there is a C.T.C.-controlled dwarf signal to direct a train, on the siding, to depart. This move is made by trailing out through the spring switch. so no stop is required for trainmen to handle the switch.

Plan of signaling for siding to siding block.

Power switch machines are used at entrance end of sidings.

As a general rule, trains enter a siding at the power switch end and depart at the spring switch end. Signaling is arranged, however, to direct a train to enter a siding at the spring switch end if the dispatcher decides that such a move is preferable. For example, if an eastbound train is to be directed to enter the spring switch end of Minnipuka siding. the dispatcher sends out a control to cause Signal 92.2 to display yellow over an illuminated lunar white marker which includes the letter "S" This aspect directs the eastbound train to stop short of the switch at the west end of Minnipuka. Then the head brakeman reverse the switch. using the hand-throw stand, so the train can enter the siding. After the train is in the clear, the trainman returns the switch to normal.

In this arrangement of power and spring switches, if other factors are equal, maximum flexibility of train operations can be attained by locating the power switch at the east end of one siding, and at the west end of the next. etc. This procedure was followed except where local conditions dictated otherwise. For example, a spring switch was not installed where a train would be ascending a grade when pulling out of a siding, because, at such locations it might be necessary for an engineman to back up to take up slack when getting his train started. Such a move on a spring switch might result in a derailment. Power switch machines are used at both ends of the sidings at Fire River and at Oba where trains take water. Of the 15 other sidings, the power switch is at the east end of seven and at the west end of eight.

Siding-to-siding block; no flagging

The block is from power switch to power switch. For example. from Signal 91 at Minnipuka to Signal 84 at Dishnish. or from Signal 101 at Neswabin to signal 91 at Minnipuka. The signals which authorize a train to enter a siding-to-siding block operate to display either red for Slop or green for Proceed, the latter indicating that the entire siding-to-siding block is unoccupied. There is no signaling to allow a following train to enter a block occupied by any. train. With this practice, no flagging protection is required, except for unusual circumstances, this being an important factor, especially in severely cold weather. The siding-to-siding block plan produced some saving by eliminating intermediate automatic block signals, as such. Signals such as 856 and 895, between Dishnish and Minnipuka. are approach signals. For example, Signal 856 displays the yellow aspect when Signal 84 is at Stop, or when 84 is lined up for an eastbound train to enter the siding.

How trains save time

The C.T.C. on the entire subdivision is controlled by one machine in the dispatcher's office Hornepayne. The illuminated track diagram on the machine indicates the location and progress of all the trains. so that the dispatcher can control the signals to direct trains to make close meets. An important benefit is that the C.T.C. has enabled the dispatcher to eliminate the train congestion which formerly occurred nearly every after noon on this subdivision. Now he can handle the six passenger trains on schedule, and also keep the freight. moving. Formerly. many of the freights ran into overtime (more than 12 hours), hut now such a thing is unknown except in case of accidents.

With train order operation during the first three months of 1951, manifest freight trains averaged 8 hr 19 min. for the subdivision. as compared with 6 hr. 19 min. in the same month. of 1952 (using C.T.C.). a saving of about 2 hours in 148 miles.

During the summer of 1952, an extensive reballasting project was under way on this entire subdivision, requiring numerous slow orders and many work trains. In spite of this interference, the manifest freight trains saved an average of 1 hr. 3 min.. and the drag freights 1 hr. 44 min. eastbound. and 1 hr. 13 min. westbound. These figures are for all such trains in July of 1951, compared with July 1952.

Spring switch mechanisms were installed at the leaving ends of sidings.

With no slow orders or work train interference in 1953, operating officers expect that the time saving ascribable to the C.T.C. will be about 2 hours for manifest trains, and 3 hours or more for other freights. These savings arc accomplished primarily by making closer meets by means of the C.T.C. For example, on September 25, passenger trains No. 2 and No. 3 made a nonstop meet at Minnipuka.

In a meet between two freight trains at Neswabin that same afternoon. the actual standing wait for the eastbound train, on the siding. was only 35 sec., measured by a watch on the locomotive. The westbound train passed at normal speed. If train orders had still been in use, the westbound train would have taken siding at Minnipuka, 10 miles east. Thus, in this instance the C.T.C. saved about 40 min. for the westbound train and did not delay the eastbound. On September 25, the same eastbound freight continued east to Fire River to take siding at the west end while passenger trains No. 1 and No. 2 made a meet. Then a11 three trains were soon on the move again.

Snow plow run cut one day

Previously, with train orders; two days ordinarily were required to run a snow plow in either direction between Hornepayne and Foleyet. With C.T.C. this snow plow run is being made in one day. Previously, freight trains were not called to depart from Foleyet or Hornepayne in the late forenoon as time approached for the parade of passenger trains. Now these trains depart as soon as they are ready.

No records are available of the time saved in this respect by the C.T.C.. but the chief dispatcher states that ability to instruct a train to leave Hornepayne or Foleyet the moment it is ready is saving many hours that were not shown on the train sheet previously.

The final section of this project was placed in service on December 14, 1951. An immediate cash benefit was that the employment of 13 extra operators required to place absolute block in service during winter months was not necessary. In the course of a few months, other offices were closed either part or full time, so that 17 more operators were moved to offices west of the C.T.C. territory, where they were needed badly.

When there's snow in switches

When all the siding switches Were operated by handthrow stands, the track crews cleaned the snow from the switches during and after snow storms as part of their regular duties. Brooms and shovels were on hand, placed at the switches for trainmen to clean a switch if necessary when operating it. These same practices are being continued, with respect to the power switches and spring switches in the C.T.C. In the new concrete relay house of each power switch there is a separate room 7 ft. by 8 ft. with a stove, for use as a phone booth, and as warming room for track forces.

In this area, snow falls as soft flakes, and the air is still, with very little or no wind in cold weather. Therefore, ordinarily, snow does not drift into switch points too much, after they have once been cleaned following a storm. If a spring switch does not close to the normal position after a train trails out through it, the dispatcher can tell this from the track occupancy indication. and can call trackmen to clean the snow or other obstruction from the switch.

In brief, the spring and power switches. as well as all the other signaling facilities in this C.T.C. project, are operating successfully in an area 200 miles north of Lake Superior where winter temperatures range from 25 to 40 below zero for weeks. The record low in the past few years is 72.6 deg. below zero F.

This project was planned and installed by Canadian National forces under the jurisdiction of H. L. Black, system signal engineer, with headquarters at Montréal, and under the direction of E. P. Stephenson, signal engineer, Central Region, at Toronto. N. W. Mountain, superintendent of signals of the Northern Ontario district, had charge of field construction forces. The major items of signaling equipment were furnished by the Union Switch & Signal Division of the Westinghouse Air Brake Company.

Ref: Oba Subdivision