1) Yes, you can use PAYG on West Midland Trains between Euston and Watford Junction.
2) Yes, they do still run. The planner shows the fastest routes and the Overground trains generally get overtaken by the faster West Midlands trains.
When you say I can use pay as you go on West Midlands trains, does this mean I tap in on the barriers at Euston and tap out at Watford Junction, basically like I would on the tube train?
How frequently do the West Midlands trains run when compared to the London overground trains?
Apologies for all the questions, but I’m not from the area and just want to be sure before we travel.
Yes, you touch in and out in the same way as you do for the Underground. There appear to be 4 trains an hour for each of West Midlands and London Overground.