Not sure what the dreaded routing guide makes of this but NRE‡ is totaly confused.
...
No wonder people don't travel by train.
While the current emergency reduced timetable explains why there's a fare defined that can't be offered for sale, it is still "the timetable" in force now. So the routeing guide should still apply. The definition of a permitted route depends on the availability of trains, so some routes will temporarily not be permitted. I think that has some side effects that are not obvious.
The guide refers, in this context, to "through train" (which is defined in its glossary), "direct train", and " regular scheduled train service" (neither of which is defined). Do they all mean the same thing? I suspect so, but it all adds to the feeling of confusion. That's particularly the case here, where the result depends on concluding that no such train exists for any of those any definitions.
So what does the guide say? Castleford is a member of the Pontefract routeing group (or possibly the Pontefract group routeing point, if that's different), and Sherburn-in-Elmet is a related station of that routeing point. So, as the calculator provided in the guide says: "This is a local journey via a common routeing point - use local journey rules defined on page F7 of The National Routeing Guide in Detail (Section F)." Page F7 is not much help, in this case. It does look as if there is no permitted route. If so, it does make sense that the
OJP▸ offers those two-ticket alternatives. At least, it does if you accept the principles underlying the routeing guide - which you may not.
Worse things can happen though. Pontefract group includes not just Glasshoughton and the two Pontefracts on the Wakefleld line, but also Baghll which is on the line to Sherburn. Baghill and Monkuill stations are not far apart - about 1 km for a walking crow, less if you can fly. So why isn't it offered as a walking route? A bit far, but given the lack of alternatives some might use it to get from CFD to SIE. That would be a lot cheaper, except that there are currently no trains stopping at Baghill. Even when there were (or will be) the service is "sub-Melksham", so most of the day it would not even be quicker.
But what happens if you ask the OJP for a journey between Pontefracts Monkhill and Baghill, both members of this group? In September, it offers no single fare, just two tickets for a trips via various routes. This takes over two hours each way, and two singles (no return is offered) costs at least £49.00! The routes it offered me are via Castleford and Meadowhall, Leeds and York, Leeds and Sheffield, and Wakefield and Moorthorpe. BRFares says in that case there is no fare - and remember, that's within a group.
If you ask for a journey next week, you get this:
This journey is not available.
There are no journeys available at the time, on the day, or on the route you have selected. Here are some of the reasons for how you got here.
Planning a journey during a Bank Holiday Period.
During these periods, there are often major engineering works taking place across the network. This is often why stations are closed during these periods, and the Journey Planner cannot plan a journey.
The route is closed.
It is possible that the particular route you have specified has been suspended with no alternative mode of travel, such as bus, Tube or tram. Removing or changing a selected 'via' station may provide alternative routes for your journey.
The Journey Planner should always find the best available route for the journey you want to make. If needed, network maps showing alternative rail routes can be found here.
The timetable is not yet confirmed.
Timetables are usually approved and set into the Journey Planner 12 weeks in advance, but during periods of extreme disruption, train services may be confirmed in less time.
You can try checking for the journey on another day, or closer to the day you want to travel.
None of that's really telling it like it is. And why has that page not had a bit added to cover journeys not possible under the emergency Covid-19 timetable?