You mean somewhere like Chathill? Passenger trains pass through the station in both directions without stopping, but if you board a train that calls there, your only option is to go south.
Not the one I am thinking about.
To clarify, there are "Up and "Down" running lines through the station with passenger services on them but only "Down" trains stop. To travel in the "Up" direction you have to catch a "Down" train and change at the next station and come back through.
I am not familiar with Chathill so I can not say if that is the case there. I assume you mean it has a bi-directional service and both go in southerly direction.
Ah, right. You may be thinking of Polesworth then?
Ribblehead (southbound) and Bromsgrove (northbound) used to only have one platform so trains could only call in one direction. Both have now had a second one built.
Now for a bit of rule-bending...I'm going to try and throw Reddish South in for consideration. AFAIK there's only a single road running through the station (With only 1tpw in any direction!) but it's bi-directional.
Bedwyn..
Only served by trains from the (east) London/Newbury direction.
If you wish to travel from Bedwyn westwards then travel east to Newbury before catching westbound train non-stop through Bedwyn
Reeves Corner on Croydon Tramlink has trams passing in both directions but you can only board a tram heading into Croydon, not going the other way (except when it's used as a terminating place during engineering work)