TfL have not made public their modelling for Crossrail 2. As such, I've done some journey time modelling myself.
Journey time modelling
Journey time modelling is a hard problem in general, as there are many possible routes to consider on a network like that in London. However, if the problem is simplified to only include a subset of routes, it is possible to obtain an answer.
The simplifications used are:
- Only journeys from SWML destinations affected by Crossrail 2 are considered
- Only journeys to central London destinations are considered
- Interchange times are estimated
- A maximum of three trains is allowed to get from start point to destination
- Buses are ignored
- Trams are ignored
- Walking is ignored
- Time to enter/exit stations is ignored
Even with these simplifications, it is possible to get some reasonable figures out, and take a look at two key questions:
- Will Northern Line passengers change onto Crossrail 2?
- Will Crossrail 2 passengers change onto the Northern Line?
The results are here:
- Crossrail 2 via Balham (TfL plan)
- Crossrail 2 via Tooting Broadway (TfL old plan)
- Crossrail 2 via Earlsfield (Swirl plan)
- Crossrail 2 via Earlsfield with branch to Balham/Streatham/Tooting (Swirl-Max plan)
Each page contains a set of possible options for each of a long list of possible journeys. A key of station codes is given at the bottom of each page.
The first finding matches that of my previous article. Journey times from Crossrail 2 suburbs to London Bridge and Bank are quickest by changing onto the Northern Line.
The second finding was unexpected however. The figures for Balham indicate that many passengers travelling from Morden to Victoria and Euston will not change to Crossrail 2! This is because the time saved by the new route is not enough of a saving over the existing route (changing to the Victoria line at Stockwell).
Finally, it is important to remember that the time to enter and exit the station is not included. This can have a big impact together with the walking distance to an individual's actual start and end point.
This quick post provides links to journey time analysis for Crossrail 2 in South West London. The analysis is imperfect, but enough to raise further concerns about TfL's Balham option.