I don't know the geography of the area very well and unable to check the routeing guide at present. Can anyone help? Is a London - Pilning Super Off Peak Return valid via Cardiff Central? So go London - Cardiff - Pilning?
National Rail Enquiries indicates that you would need to buy a London-Newport (or London-Severn Tunnel Junction) ticket plus a Newport (or STJ) to Pilning ticket if you wanted to go to Pilning on one of the two eastbound Saturday trains that are the only trains each week to call at Pilning. And there are no Routeing Guide easements allowing travel to Pilning via stations west of Pilning.
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To allow journeys on Saturdays to Pilning from Bristol Temple Meads to travel via Newport South Wales, this routeing point easement will override fares checking in journey planners.
Actually there is a routeing guide easement:
But it seems to be interpreted very literally, i.e. journey planners will show a Bristol Temple Meads to Pilning ticket as valid for a journey via Newport, but not valid for the shorter journey via Severn Tunnel Junction. And the easement is not being used to validate journeys to Pilning via (rather than "from") Bristol Temple Meads, let alone from/via Bristol Parkway.
I think that what the easement needs to say is something like: "To allow journeys on Saturdays to Pilning from or via Patchway to travel via Severn Tunnel Junction or Newport South Wales ..."
STJ hasn't really got a lot going for it in terms of being a nice station to spend 40 minutes
Neither's Newport!
At least Newport has a toilet and a little shop