Unfortunately, Scotland will not be as big a contributor of spare DMUs over the next few years as was hoped - with the EGIP scheme scaled back to just the E&G mainline for now, with Stirling/Falkirk/Alloa/Dunblane 'delayed' into the next control period. Hopefully this will still go ahead.
Meanwhile, Paisley Canal wiring will free up a pair of 156s, which are more than likely to be retained by ScotRail for strengthening services or eliminating the Fife loco hauled service - the 156s return to the Whifflet turns, with the 158s currently diagrammed replacing the 67 turn for example.
E&G wiring will free up something around 12 to 14 170s by 2015 - a good number to start a cascade going. I would suggest that is a sufficient number to warrant getting clearance for the class on the GSW routes - Glasgow/Carlisle/Newcastle/Stranraer - along with all the relevant crew training. This, combined with plans to progressively wire Whifflet, East Kilbride, Kilmarnock and the Shotts route over the next few years, will lead to the 156s being eliminated from Glasgow southside services with 170s covering the non-electrified services over the Newcastle-Carlisle-Kilmarnock-Ayr-Stranraer sections.
Very few 156s operate non-WHL services out of Glasgow QS, mostly marginal time workings between WHL turns, but some big decisions will have to be taken on WHL traction soon. The far North and Kyle are fine with 158s (especially the refurbished 701-725 batch) and indeed, Inverness could do with more 158s for Aberdeen services as passenger numbers continue to rise with 4-car 158s replacing 3-car 170s. Indeed, ScotRail's longest train DMU set currently works out of Aberdeen - a 7 car evening departure of 2x158s and a 170!
This leaves the WHL conundrum... Options?
1. A heavy refurbishment of around a dozen 156s, with new seating, air con, new disabled access toilet and possibly re-engining to cope with the extra power demands of air con. Option likely to be expensive and how far will the leasing company go in investing in 25 year old stock?
2. Route clearance for 158s, made available by cascading 170s freed from E&G wiring on to Fife/Dunblane services. The IS based refurbished 158s are fine on the similar Far North/Kyle lines, with decent seating arrangements to allow a good view of the scenery on these lines. Whilst the use of 90mph on these lines is not ideal, the 158s are still pretty good off the mark and hill climbing - maybe not as good as the lower geared 156s, but better than the lethargic 170s. Option likely to need unknown Network rail investment to route clear the WHL for 158s, despite the stock being already suitable inc RETB fitting, etc. Service pattern can be retained with joining/separation of trains at Crianlarich.
3. Route clearance for 170s, made available from E&G wiring. Again, unknown costs of route clearance, plus 170s not RETB equipped or fitted with corridor connections, bringing complications south of Crianlarich as regards ticket checks and trolley services. Gearing of the units is also rather high for a route where lower speed acceleration and hill climbing ability are more important than top speed. Re-gearing of the units could be contemplated, along with a refurb of the interior with internal doors by the entrances to minimise the effect of the saloon being open to the elements when the doors are opened!
4. New build, something like an LM 172, 2 or 3 car sets with corridor connections. Possibly only around 10-12 sets required as by 2019, the only diesel services out of Glasgow QS will be the WHL turns. Again, expensive and will the leasing companies invest, given the expected glut in DMU availability in the 2020s as electrification spreads?
