Maybe not exactly what you're looking for, but I recently learned about Traksy and Realtimetrains, which both give some interesting live information.
UK Rail and Trains
Talk about the UK rail network.
They look interesting. I'll try them out over the next few day.
https://www.opentraintimes.com/ Is quite detailed. Also good for checking how late your train was for Delay Repay purposes, especially as you can bookmark a particular service to refer back to later.
App wise I use Train Track by quatabyte on Android, Train Home by Thomas Thorpe on iOS.
Also realtimetrains.co.uk works well in a mobile browser though they no longer do an app.
I think you can bookmark services on all the sites mentioned here. Although, I suppose, some sites may delete the services once they've arrived.
Probably. I know that I've copied the OTT URL for the service's page into the notes field in a calendar entry before travelling, and it still works a couple of weeks later, although if I go back further it says "Schedule L15359 was not valid on 2024-03-19", so I'm guessing they get dumped after a month. Probably a limitation of the Network Rail data/licence.
I should have also mentioned Open Train Times. A bit more technical but the maps are useful for seeing where your train is, if it's delayed.