The 239 and the 4 on a night operate on a combined 30 min frequency on a night from Houghton to Fencehouses Railway Crossing.
Obviously the 4 continues towards Washington, whilst the 239 heads through Avenue Vivienne covering for the lack of a night time service on the 36.
On the return leg towards Houghton, the two services follow each other from Edinburgh bakery.
Not a bad little frequency at that time of night - two services 30 seconds apart.
Ideal if you miss one as the other isn't far behind.
Given the scope in timetables and lack of provision at Rainton Bridge on a night (despite people working down there and there being events on at the grandly named Rainton Meadows Arena), I wonder if it would be worth sending one of the services down there on a night and on into Houghton via the A690.
There shouldn't be too much difference in mileage.
The timetable is slack anyway (particularly the 4) and there is the potential to pick up a few more passengers. Rather than have one service shadow the other for a few miles.
RE: Go North East: Service Suggestions