How Much Has Subway Service Improved?

Updated September 9, 2021: The TTC has clarified the service improvement that was implemented. See How Much Has Subway Service Improved? (II).

On September 7, I tweeted about a City of Toronto press release that, among other things, touted a planned improvement in subway service:

My tweet:

Fact check on a City of Toronto press release: “To accommodate increased demand in September, the TTC is increasing service system-wide to support the expected increase in ridership, including 25 per cent more subway trains on Line 1 and Line 2 at peak times on weekdays…”

2. The actual change in peak services are: Line 1 peaks were every 3’45”, now every 3’30”. Line 2 changes from every 4′ to 3’45” during peak periods. Count of scheduled trains goes up partly due to more gap trains (spares), longer Line 1 travel time, and more frequent service.

3. Change in capacity is about 7%, not 25%. The number of trains changes from 43 to 50 on Line 1 (+16%), and from 27 to 31 on Line 2 (15%). Capacity is driven by trains/hour past a point, not by total train count.

4. The press release overstates the actual change in subway capacity during peak periods.

5. Early evening service is improving substantially. Line 1 from every 5′ to 3’30” (43%), Line 2 from 7’15” to 6′ (21%). Late evening Line 1 from 7′ to 5′ (40%), same change as early evening on Line 2.

6/6 Why are the City and TTC overstating the peak improvements?

TTC’s Stuart Green replied somewhat later in the day:

Oh, Steve. Looks like I have to interrupt my vacation to correct you. Ten trains more. 43 in August 53 in Sept. (some additional trains added last minute based on demand expectations). 23.25 per cent. We rounded to 25 based on commonly accepted rounding practices.

The problem is that available TTC information, on which I based my claims, says nothing about those extra trains, but matches what I have published here and written on Twitter.

Source: TTC Website copied September 7, 2021
Source: TTC Website copied September 7, 2021

Another source of scheduled service information is the electronic version of schedules that are published on the City of Toronto’s Open Data site by the TTC. Without going into the mechanics of reading these, they clearly show the 3’30” and 3’45” headways advertised above for Lines 1 and 2 respectively.

This information also corresponds to what is stated in the Board Period Memo issued by Service Planning on August 13 (this memo is the basis for my regular previews of service changes).

Service will be restored on Line 1 in anticipation of ridership returning to the transit system. On Monday-Friday, service on Line 1 will be restored to January 2021 service levels, with two additional gap trains for demand responsive service (increasing to four gap trains).

Service will be restored on Line 2 in anticipation of ridership returning to the transit system. On Monday-Friday, service on Line 2 will be restored to January 2021 service levels, with two additional gap trains for demand responsive service (increasing to four gap trains).

TTC Board Period Memo issued August 13, 2021

Note that restoration is to January 2021, not 2020 or pre-pandemic levels.

Below are excerpts from the TTC’s Scheduled Service Summaries for August and January 2021. Note that the round trip time for Line 1 is 161 minutes in January, but only 154 minutes in August. Some of the “restored” trains simply go to extending the trip time, not to providing more capacity. On Line 2, the round trip times are almost identical (101 vs 100 minutes).

Every source I have for info on how much service is running says that there is a smaller percentage increase than the press release claims.

Moreover, the press release uses the change in train count as an implication of a capacity increase greater than is actually provided.

This distortion arises from various factors:

  • Of the seven trains added to the Line 1 schedule, 2 are gap trains that are inserted where needed on the line. They may or may not add to the total service provided depending on where and when they are used.
  • Changing the scheduled headway from 3’45” (225 seconds) to 3’30” (210 seconds) would require 3 additional trains if the travel time were not changed. Providing extra travel time requires two more trains.
  • The TTC says that they have added three more trains above the scheduled level (49 versus 46 regular trains). If these are integrated into the schedule, the headway would fall to 3’17” rather than 3’30”. This is still only a 14% increase in capacity versus the August schedule of 3’45”.
  • The rounding used by the TTC from 23.25 to 25% is equivalent to almost an entire train. This is not a trivial rounding error.

A 25% increase in the number of trains does not translate to a 25% increase in service capacity because four of the additional trains are added as gap fillers or to stretch the scheduled travel time.

The press release states that this is applicable to both Lines 1 and 2. If extra trains above the scheduled level on Line 2 were also added, the TTC has been silent on the details as I write this.

Between extra trains the TTC has added and counting trains in service rather than trains/hour past a point, the press release claim of 25% more trains is correct on its own terms. However, it gives the impression of a greater increase in service capacity than what is actually provided.

This is a subtle but important difference. Tempered by accepting that the TTC has added three more trains to Line 1 service than shown in previously published information, I stand by my statement that the City’s press release exaggerates the degree of service improvement.