I now understand a bit more about this station following on from calling at the station on the recent meet - it is on an otherwise freight line and the two lines, I believe, are essentially independant, though I'm not best placed to explain.
The (double track) line between Brocklesby and Immingham is essentially the 'through' route at Ulceby nowadays. The single line from Habrough runs onto the Down line immediately south of the station, and the single platform is on that line. There's then a trailing (to 'through' freight traffic) crossover which takes the Barton units onto the Up line, and finally through the single lead onto the Barton branch proper. You can see the layout on
this photo from
www.tillyweb.biz - Ulceby station at the bottom, Barton towards the middle right, and Habrough (which Ulceby controls with a small IFS panel) top left. Brocklesby is top right, obviously with its own signal box.
I believe the first service is run by 185 as the 153 normally used is not in place so early on a morning (it comes in by ECS move from Sheffield IIRC) - it also doesn't call at all stations as the platforms in some places are too low to safely disembark the 185's.
I'm not sure exactly what time the unit comes across from Sheffield (or Doncaster?), but the big problem is that there's departures from Cleethorpes at both 0600 and 0700 - so even if the empty unit was there in time for the 0600, there'd then be nothing to work the 0700. The unit from the previous day then runs ECS to Scunthorpe to form the 0810 onwards from there; if it worked either of those two Bartons, it wouldn't have time to do that - though it might
just be possible if the 0658 (??) ex-Barton terminated at Grimsby Town and went ECS to Scunthorpe from there. Why go to all that bother though, when there's a unit sitting at Cleethorpes with nothing to do until around 0830?
Something else of note is that the services although run by a Northern 153, are manned by a TPE crew.
Correct. Not sure whether any Northern crews still sign the route - I think some Doncaster drivers did previously though, and were used when TPE were struggling to provide traincrew.