- Where service patterns differ by time of day and/or day of week, mapping should follow weekday midday service, with the exception that tracks which only see service part time should be mapped regardless of when their part time service is
To expand on this...
1 thing I've found is that some British operators have infrequent (say 1 to 4 times a day) extensions of long distance services to places that they wouldn't otherwise service, but are wholly concurrent with other operator's services (or even their own - eg GWR to Paignton to give a direct London service, but most trains are stoppers as part of the 'Devon Metro'). Do I implement a train-every-two-hours cut off for this? Certainly it would help with reducing concurrencies (cf Avanti West Coast to Blackpool, or TransPennine's Liverpool-Glasgow services). Obviously services using unique bits of track would get added (which I need to implement when it comes to some peak urban services), as would stuff like the Caledonian Sleeper that is, by nature, infrequent service.
London North Eastern Railway's wikipedia page implements this well, splitting its service table into 'Regular Services' (hourly or 2-hourly), and 'Irregular services' (1 to 3 trains per day).
CrossCountry's wikipedia page removes them from the service table and lists them in text form.
I don't know what the frequency cut-off for service being 'limited' is on
Project Mapping's map (used by National Rail), but it strikes me as perhaps a little too low as a cut off.
Also, if we're going by midday service, why did this get implemented?
This is fairly easy to resolve using some local knowledge of the administrative history: all the lines which pass through Newark Broad Street can be mapped as terminating in Hoboken, as historically they all did before the introduction of "MidTown Direct" service on these lines.
The only trains on the Morristown and Montclair-Boontown lines that go to Hoboken are the ones that extend beyond the electric network (the Gladstone branch usually goes to Hoboken though) and a couple of peak trains.
https://content.njtransit.com/sites/default/files/ME-WKDY-042323.pdfhttps://content.njtransit.com/sites/default/files/MC-WKDY-042323.pdfThis strikes me as an odd move - more based in nostalgia than actual service. The solution done on the LIRR to reduce the concurrencies (most frequent wins) strikes me as a good one. The most-frequent terminus for two of the three Newark Broad Street lines is NY Penn and so they should go there. If you took a Hoboken train, you can map it as using the Gladstone branch - just as mapping a Huntington - Grand Central journey on a direct train the other side of the Hudson needs to use one of the routes going between Jamaica and Grand Central.
This at least is the situation where you only have branching in one direction. Where you have branching in two directions I don't think every single possible service pattern necessarily needs to be mapped (in some cases that could get to be quite a lot) so long as every branch is included in some way. You'll see, for example, the way I've retooled LIRR, I've generally sorted the outward branches between Atlantic, Penn, Grand Central, and LIC based on which one the majority of trains on that branch go to, with a couple branches having both Grand Central and Penn versions because the number of trains to both is near parity.