Talk:Train routing

Is this usable without timetable?

Is this usable without timetable, or at least general frequency, information? As an example, the Gospel Oak-Barking Line is 2tph and thus should be avoided compared to other more frequent railways. Are there external timetable sources we could use? Morwen 10:42, 9 November 2007 (UTC)

Is that information that we could easily add? e.g. anyone who lives in Weybridge could tell you without looking that there are 4 trains per hour, and list the stations you can get to on that line.

Added discussion below on the various 'levels' of routing fidelity Ojw

I agree with Morwen here, there's no use in doing "routing" with public transport networks without timetables. You can't travel on a railway line without a train being there. Any route that uses frequency of trains can only give you a "most likely" quickest route between two stations, but if the suggested route has a couple of changes of train along the way, then the "cost" of missing that connecting train will be relatively large. E.g. if you miss a train at a connecting station and end up with a half-hour wait for the next one, you could have been 30-50 miles further up the track if you'd stayed on the train - and could maybe have caught another train on a different line which gets you to your destination much quicker. If there are connecting trains, then only a timetabled solution is likely to have any value for a train traveller. Richard B 13:45, 12 November 2007 (UTC)

In your case of connecting trains (arguably a very complex case to start with) then you can calculate the expected and worst-case waiting times based on the frequency of trains. And if any trains are delayed, then that approach is better (less brittle) than one which uses a timetable. This is the algorithm used by london underground travellers (when did you last go for a specific train on the bakerloo line? do they even have timetables?) Ojw 19:20, 14 November 2007 (UTC)

I wasn't necessarily thinking of something like the London Underground - with very frequent trains on a dense network. I was thinking more of Network Rail type routes - and potentially long distances between start location and finish location. I wouldn't exactly say a route involving more than one train was exactly an atypical request for someone planning a journey. When you type in a route, you expect to be shown the optimal quickest, perhaps with certain restrictions based on cost etc. If you are told by the router to disembark at a station where there isn't a scheduled service for the next half-hour, your time *could* have been better spent travelling to a different station further along the line which perhaps did have a service taking you to your eventual destination more rapidly. You can go quite a long way in half an hour on some trains - particularly on things like Intercities which stop at several hub-stations along the way. Richard B 01:14, 15 November 2007 (UTC)

Purpose of this page/Rewrite this page

I propose to rewrite this page. At its current state, the page presents some ideas or concepts of routing train passengers with or without timetable data. It remains unclear what the purpose of this page is.

However, in the last two years two (or more?) applications to route trains on OSM data emerged. I think that it would be more useful to write a bit about them here, not to write about some theoretical concepts of train routing. This is a wiki about OSM not a wiki about processing of information with a spatial context. --Nakaner (talk) 21:27, 21 July 2019 (UTC)