The issue with TSR's being used for timings at level crossing or sighting issues, is the length of time they're in place before they tend to become permanent. Prestatyn had a 75 imposed for a long time, Macclesfield still has one on the up. If NR won't spend the money on bridges or Banners, then the PSR should be introduced much more quickly. NR shouldn't be able to leave them on for such long periods. Obviously it doesn't properly solve why this failure happened but it would make it less likely.
To defend NR a little here, there have been numerous "problems" with UWC's along a section of the Cambrian. The proposal from NR was to close several of them, and build a new road and bridge. The time taken, which may seem long to some, was because each farmer had to be negotiated with, and many had their own ideas and didn't/wouldn't talk to each other, they had to design a suitable bridge and route for the road, purchase the land for that road, obtain permission from the Highways Agency and the County Council to alter accesses, apply for Traffic Regulation Orders to close and divert Rights of Way, apply for Planning Permission and then contract for the work. Many of these things could not be done at the same time as there are proceedures laid down that specify the order they have to be done.
There are no short cuts to make it quicker in many cases! For example, it only needs the Ramblers Assoc to complain about diverting a Footpath and you can end up with a Public Enquiry that could take 2 years; it has happened.