Remodelling of the Grand Trunk Railway Ottawa Terminal yards.
By Alexander Gray, A. M. Can., Soc. C.E.
In giving a brief account of the work of remodeling the G.T.R. central station yard in Ottawa it would be superfluous to review the reasons which led up to such work, further than to say that when the Canada Atlantic Ry. was fortunate enough to secure this route to the heart of the city, the terminal was not designed with any consideration of future requirements. Tracks and other railway facilities were built by degrees as demands arose and property was acquired. Under such conditions it was only a question of time until all the available land north of Laurier Ave. was taken up with a jumble of tracks which were very difficult to operate and in an exceedingly poor state of repair, the rails being 56 lb. steel and the switches stub. When we came to consider the remodeling of this yard, the problem which confronted us was not to design a yard by using up the old one, but to design one without any regard for existing conditions, a yard giving the facilities for passenger and freight accommodation.
The passenger and freight yards are entirely separate from south of Laurier bridge, and as both the passenger and freight business enter from Besserer St. the grades of the tracks are governed by the grades of this street. From the station entrance towards the freight shed there is a drop of about 6 ft., which makes the passenger yard ascend from Laurier bridge towards the station and the freight yard descend from Laurier bridge towards Besserer St. While we were anxious to have the two yards of a uniform grade, it was impossible to obtain this without very considerable expense both in land damages and in bringing up the adjacent streets to such grade. With the present arrangement there is excellent drainage for these two yards. The 20 ft. roadway between the two ladder tracks may be called the water shed. The passenger yard drainage runs towards the canal and Laurier bridge and the freight yard drainage goes towards Besserer St., where it grains into a sewer at Musgrove St. This was one of the difficulties in the old yard, there was no drainage, which meant a lot of heavy maintenance work during spring and fall weather.
G.T.R. Central Station yards, Ottawa, from Laurier Avenue bridge, Sept. 17, 1909, before improvements.
G.T.R. Central Station Yards, Ottawa from Laurier Avenue bridge, Jan. 17, 1910, showing improvements made.
In the centre of the old yard between Laurier Ave. and Besserer St. there was a hump of about 3 ft. and as the tracks were lying on blue clay with little or no ballast underneath, a steam shovel was put to work and excavated the freight yard for tis entire width and right through to Besserer St. to a uniform grade of 1/10% and to a depth of 2 ft. below the base of rail. At the side of the tracks under the transfer platform the excavation was made about 18 ins. deeper, in order to have the sub grade of the tracks thoroughly drained. This arrangement gives a very dry yard in all weather. Part of the excavation from this point was dumped into the old canal basin where the freight shed stood on piles, this part having never been filled in. With this work all surface traces of the old canal basin have now been obliterated.
In the carrying out of this work the chief point we had to keep in sight was the safe and speedy operation of present business. The freight facilities were so congested that we could not cut out one track without making provision for its business at some other point. It so happened that part of the new freight shed was located on vacant, thus enabling us to build the freight office and about 300 ft. of freight shed and two the of the freight tracks before disturbing the old shed, which was located where part of the main passenger ladder track now runs. As the new tracks peculiarly cross the old tracks diagonally, a good deal of study had to be given to each move made, so that freight business would not be tied up during the construction of any of the new works.
The rail in the freight tracks is 80 lbs. and the switches a split with no. 9 frogs, thus having leads which will admit of a safe operation by the ordinary class of engines, although there is a special yard engine to do all the switching work in the yard. The maximum curvature is 9 1/2 degrees, which is the turnout for a no. 9 frog. Up to the time of writing there have not been any derailments in this yard since its completion, whereas previously there was an engine off the track on average every 24 hours.
The freight yard consists of a freight shed and office 668 by 30 ft., with four parallel tracks the full length of the shed. A transfer platform 560 by 16 ft. and three pairs of unloading team tracks with macadamized roadways 30 ft. wide are also parallel with the freight shed. The floor of the freight shed is level with the floor of cars standing alongside. Freight can thus be loaded or unloaded into the cars through the shed. Opposite every alternate door in the shed is a set of weight scales set in the floor, which saves a considerable amount of trucking.
The passenger yard tracks are in pairs 13 ft. centres, with room between each pair of tracks for a platform 19 ft. wide. The shortest pair of tracks have a train capacity of eight cars each (figuring average length of car over all at 70 ft.) and the longest can hold 17 cars. The total train capacity of this yard is 100 passenger cars, which figures out of a little more than double the train capacity of the old passenger yard. The passenger yard tracks are built of 100 lb. rail with no. 9 frogs. All the switches are on the one ladder, which gives the engine driver approaching the yard a clear view of the condition of all the switches. Ultimately it is the intention to have all these switches interlocked, the tower to be located either on or near Laurier bridge. A train shed of the Bush type, 500 ft. long, covers all the tracks from the baggage annex to the canal. The tracks are ballasted with crushed stone which will down the dust in the station vicinity. The platforms are concrete at an elevation of 7 ins. above the top of rail.
In the passenger yard layout, in order to provide a through second track for the C.P.R. in the event of its double tracking its lines across the Alexandria bridge, we had to build a retaining wall 1,079 ft. long of an average height of 17 ft. Before commencing work soundings were taken with an iron rod along the side of the wall at intervals of about 25 ft. Instead of these soundings going to rock (as the man who took them reported) they only went to rock for about half the length; the rock extended from Sappers bridge end of the work for about 550 ft. and then suddenly disappeared; its place being taken by large boulders and gravel. The profile showing these soundings was so uniform that there were no grounds to question the results. This shows that no reliance can be placed on this method of sounding. The only safe way, in my opinion, is to put down test pits.
Designing the wall on this profile we figured on a rock foundation throughout and at the south of Laurier bridge end of the work for a distance of 137 ft. concrete piers 9 ft. 10 ins. by 5 ft. and at 12 ft. centres were built and put down in each case to the boulder foundation. Sheet piling was used in putting down these piers. The sheet piling was 3 in. lumber and drive with an ordinary pile-driver, only instead of the 3,000 lb. hammer a piece of pine, 12 by 12 ins.,. was substituted; as the hammer simply split the piling pieces. When we reached the boulders we experienced very great difficulty in driving and keeping the proper alignment, in fact we found it almost impossible to go to any depth in this foundation, as some of the boulders were so large that they had to be blasted to be taken out. There was little to be gained in looking for a better foundation than this. The piers are connected to each other by a concrete slab 2 ft. thick and reinforced with old rail. Where the wall did not rest on piers we widened out our footing 12 ins. and put the wall about 3 ft. deeper than originally intended, so that it would not be undermined in the event of the Rideau canal being deepened to a 10 ft. draught. The outside face of this wall is 13 ft. from the centre line of the first passenger track. In the design we had therefore to take care of the train load as well as the ordinary surcharge of earth pressure. Expansion joints were placed every 25 ft. and the concrete was laid in alternate 25 ft. sections.
The cost of excavation work was pretty high. On account of the through C.P.R. main lines being 26 ft. from the face of the wall and having to keep this track clear at all times we had to dump the excavations into the bed of the canal and after the wall was completed handle the excavations again, part of it with a derrick and the remainder by shoveling on to platforms and from there to cars. There was 4,800 cubic years earth excavation, which cost $1.44 a yard, and 450 cubic yards of rock, which cost $2.10 a yard. The total cost of excavation, including back fill and disposing of waste material, was $7,862.15. The sheet piling for piers cost about 3¢ per cubic yard of the total concrete in the wall. There were 2,880 cubic yards of concrete. The total cost per cubic yard, including excavation, sheet piling, walling, and everything in connection with the work was $8.43. The cost of concrete may be divided up as follows: Forms, 93¢ per cubic yard; sand, $1.087; crushed stone, $1.364, cement, $1.17; mixing and placing, 70.8¢; old rail for footings, 9.2¢; pipe for weep-poles, 1.8¢; walling, 13¢; watchman, 4.5¢; and excavation, 2.73¢ per cubic yard of concrete. This comes to, labor $3,879.7; materials $4.39, and tools 16¢ The cost of concrete, not including excavation and sheet piling for piers was $5.67 per cubic yard. All this work was done by our own forces. Work was commenced on Feb. 20, 1910, and finished for the opening of navigation, May 1, 1910.
In the remodeling of railway terminals I think it is always advisable for the young engineer to freely discuss the disadvantages of existing conditions and endeavor to discover from the men who are responsible for the operation of the yard to be designed wherein the difficult and objectionable features of the existing conditions lie. I do not wish to be understood as advising that an engineer should be led entirely by what everyone suggested, for if he did he would find himself in the same position as the man with the ass crossing the bridge. The yard men will want switches every few hundred feet, where the roadmaster will not want any at all. The master mechanic will insist upon a gravity coaling plant, where the physical conditions favor a mechanical one, all on account of saving his department the maintenance work and vice versa. When I was remodeling Bank St. yard in Ottawa before it was completed the yardmaster and his crew strongly protested that they would never be able to operate the yard for the reason that there were not as many switches in the new yard as in the old. I am safe in saying that in the operation of terminals in Ottawa 99% of the derailments and trouble were at switches. Another point in remodeling yards is that special study must be given as to how the work is to be carried out during the continuance of traffic. This is sometimes a very difficult problem, especially in congested yards.
[The writer of this article was Resident Engineer, G.T.R. at Ottawa, where the works described were carried out. He is now Assistant Engineer in Charge Upper Ottawa River Storage, Public Works Department, Ottawa.—Editor.