Are we to follow the schematic map of the stations? To collect the extra bonuses, do we have to follow them in order and join other lines where it shows a junction? For instance on the BSA line there is a junction marked at Telford that allows you to join the Ariel line, where you could then pick up the Norton line etc.
Must we follow the line in the order of the stations, for instance on the Triumph Central Line it travels from Ffestiniog to Llangollen. Can we then go to the Tal y llyn to Welshpool arm of that line as being stations along that line, or would we have to visit Nene Valley then to Severn Valley round to North Norfolk to get back on the Triumph line to get back to the Tal y llyn arm of it?
You're not alone Steve, there have been a few with questions, and the only daft question is one that doesn't get asked
There's kinda 1 answer for both questions - the map is simply an illustration of how the stations join together to make the lines for the Accumulator. There is absolutely no need to visit anything in a particular order. Any of the Stations on a line qualify for the Accumulator no matter where on the line they are.
You don't even need to visit both Stations for the Railways that have 2 - for example, the Tallyn Railway you mention, you could go to Tywyn and not Abergynolwyn if it didn't suit your plan. I did originally want to have an extra bonus for getting a pair but it was a layer of complication that was a bit too much