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The Truth Behind the Interlining Trial

Text by James Bow

Many railfans with an interest in Toronto's subway operations will know that when the Bloor-Danforth subway first opened, it was operated as an extension of the Yonge-University subway. This "interlining", which had alternate trains from the Keele and Woodbine terminals travelling either across town to the other Bloor-Danforth terminal, or downtown via the University subway and then north to Eglinton, was a trial operation that lasted for six months following the Bloor-Danforth subway's opening.

Fifty Years of Progressive Transit, page 115, states that, for an additional six months, the TTC tried segregated operation, and then surveyed its passengers to see which operation they preferred. No clear preference emerged (integrated operation had a slight edge to segregated operation, but both were overwhelmed by the number of people who didn't care either way). Thus the conventional wisdom of this story came about.

I recently happened upon a copy of the Toronto Transit Commission's 1966 annual report, and was startled to discover this issue discussed in detail within its pages. By quoting the relevant section of this report, this should provide the reader with the truth behind why the TTC decided to abandon integrated operation.

Bloor Map

This map, scanned from a pamphlet produced just after the opening of the Keele-Woodbine segment, shows the interlining as well as the extensions to Islington and Warden, under construction.

Bloor-Danforth Service Integrated with Yonge-University Subway Line

When the newest addition to Metro's subway system was opened, service on the Bloor-Danforth line was integrated with service on the north-south Yonge-University line. Alternate trains ran from the two terminals, Keele and Woodbine, to the opposite crosstown terminal and to Eglinton terminal via south on University and north on Yonge. From Eglinton terminal alternate trains ran via the Yonge-University subway and then east or west over the Bloor-Danforth line.

At the outset, the integrated system was introduced on a trial basis for six months in order to obtain operating experience on which to base decisions for future operations. The major advantage of the integrated service is that it provides passengers with a direct ride to downtown from anywhere on the subway without changing trains, as well as a direct east-west crosstown service. During the six month test period, however, several serious disadvantages became apparent. There were unavoidable slowdowns at the wye junction and although these had been reduced significantly by the end of the test period they could not be completely eliminated. Also, with the service on both lines fully integrated, a breakdown or a delay on one route frequently affected the service on the whole system. The abnormally high cost of operating integrated service because of the unbalanced volume of riding on the two lines also was of major concern. All schedules and train lengths had to be sufficient to handle the much heavier passenger traffic on the Yonge line and consequently service on the Bloor-Danforth line was much more than was required.

On September 4, 1966 the integrated service test was completed and the two subway lines, Yonge-University and Bloor-Danforth were operated as separate routes. At the year end, this second part of the test was still in progress to determine which system offers the best balance of convenience, speed and economy.

Subway Origin-Destination Survey

During the trial of integrated subway operation a large scale origin-destination study was made by the Commission's staff. The extent of this survey is shown by the following figures:



Total Daily Subway Passengers



Survey Cards Issued



Cards Returned



Useable Cards



The resulting 72% sample of total subway passengers provided an excellent base for the study, particularly when compared with the very small percentage samples (1% to 10%) which are usually obtained for surveys of this kind.

One of the main purposes of the survey was to determine the number of subway passengers convenienced or inconvenienced by the operation of integrated service. The following is a brief summary of the analysis of this part of the study:



(a) Convenienced by Integrated Operation



(b) Inconvenienced by Integrated Operation



(c) Unaffected by Integrated Operation






(a) Passengers are considered to be convenienced by integrated operation if it provides a direct ride to their destination which otherwise would not be available to them.

(b) Passengers are considered to be inconvenienced by integrated operation if they may only avail themselves of half of the service which would be available to them under separate route operation. For example, a passenger wishing to travel from Bathurst Station to Sherbourne station would be inconvenienced by integrated operation since only half of the trains arriving eastbound at Bathurst Station pass Sherbourne station.

(c) Passengers who may take any train to their destination are considered to be unaffected by integrated operation.

In addition to the information specifically related to the operation of integrated subway service, the survey provided valuable material on travel patterns, transfer movements, station usage, time-breakdowns, etc., much of which could, at best, only have been simulated through normal passenger counting procedures. The survey was a major undertaking by the Commission's Planning staff, and the results which are available on coded data processing cards will continue to be useful for a great variety of subway planning and operational applications.


The conventional wisdom that the TTC polled its passengers and asked them to state a preference as to which operation they preferred is clearly mistaken. Rather, the TTC embarked on a massive travel pattern survey, and logged passengers origins and destinations without any questions as to the passengers preferences.

The analysis is superficially convincing... until one considers that when a service operates in two branches, the usual goal is to have an equal number of people taking both. In fact, far from being impartial, the above analysis is rigged to kill integrated operation.

Consider, for example, passengers approaching St. George from the west. If equal numbers want to go east and south, then half are "convenienced" and half are "inconvenienced", and no majority exists in favor of integration. If a majority wants to go east, then fewer are "convenienced" than are "inconvenienced", and so a majority exists against integration. And if a majority wants to go south, then it might still be possible to change the segregation plan so the trains would run Eglinton-Keele and Woodbine-St.George, and once again achieve a majority "in favor" of segregation.

What the survey does not recognize is that having to wait for the second train from one's starting point is less of an inconvenience than having to change trains en route. Interestingly, this is exactly how the TTC handles things in planning service for at least the past decade. Consider the TTC's 2002 Service Plan, page 7. In this report one change of vehicles is considered equivalent to 10 minutes of extra travel time, while one minutes of additional waiting is equivalent to 1.5 minutes of extra travel time. Therefore, we can conclude that one transfer is equivalent to (10/1.5) 6 2/3 minutes of extra waiting time.

If subway trains are every 3 1/3 minutes (for ease of calculation, but reasonable in rush hour), then on this basis the people in group (a), always having to change trains, should get four times the weight of those in (b), having to wait for the next train only half the time.

In fairness, operational difficulties were a significant factor in the TTC's decision to abandon integrated operation. Two separate lines are less susceptible to delays than one unified system. But it is clear, from the flaws of this survey, and the fact that the design of the University-Bloor-Danforth wye makes integrated operation inconvenient (see the history of the University subway for more information) suggests that the TTC were not interested in making integrated operation work. One has to wonder why they attempted it in the first place, rather than sabotaging it from the design phase on.

Update: Additional Issues

After posting this article, Mimmo Briganti e-mailed to offer additional pieces of information and to correct a few items. He confirmed the controversy over the wye arrangement stretched back almost to the beginning of construction and, to some extent, its success was sabotaged. The bulk of the system delays were the result of the TTC halting all trains at the wye if a particular train missed its entry time. The TTC was more interested in preserving the sequence of trains and train crews rather than the schedule.

In Mimmo's words: "Approximately 2/3 of all trains were held for sequencing, up to 2 mins at times. The holding platforms were: Bay Downtown/Bay Eastbound (both levels) -- trains would be released alternately; St. George Downtown/St. George Westbound (both levels) -- trains would be released alternately."

In June 1966, the operation was changed to "first into the wye, first out", and the delays disappeared. Trains were resequenced at the termini instead.

Mimmo also noted that, "on June 23rd, 1966, a 4-color-card computer survey was issued to track everyone's movement on the system. 85% of all Bloor passengers heading eastbound/southbound to Queen, King, Union, and University used it vs. changing at Bloor-Yonge. 65% of all westbound passengers used it for King, Union, and University. All other passengers took thru trains to Bloor-Yonge and transferred. This was indicated on the computer survey card by removing the corner. In addition, a small percentage of southbound Yonge passengers (about 2%) also got off at Bloor and took a downtown train from the Yonge lower level to approach stations on the northern end of the University line without going around Union Stn. Reverse movements using "Woodbine" trains and transferring to Yonge Northbound were around the same percentage."

Finally, in answer to the point about westbound Bloor trains operating out of two platforms on St. George, Mario pointed out that passengers were assisted by special 4-arrow signs installed on the upper platforms of St. George and Bay stations to guide passengers to the correct platform to catch the next available train. At Bay station, a sign pointed to the westbound platform with a single arrow, and to the downtown platform with another arrow (pointing down). The eastbound portion of the sign had two arrows (one to the side and one down) which flashed to show whether the next eastbound train was to be on the upper or lower platform.

Special thanks to Mark Brader and Mimmo Briganti for their kind assistance.

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