A large part of the problem with this unit is the underframe, and the black box masquerading as a large part of it . This was fouling a point motor casting on the layout [quite possibly the one I've now resited] so it needed to go if the unit was ever to run again, quite apart from the fact it looks unrealistic and unsightly.
Fortunately I had two packs of MTK castings on hand . Not all of the castings are actually needed, since the engine blocks and a number of the boxes are already free-standing mouldings. And some of the castings are no use to man nor beast - especially the 4 cast whitemetal dartboards which are supplied in lieu of air tanks. The definitive proof that Dapol sent a development model to China for tooling which used a set of MTK castings is provided by the presence of these same curious dartboards on the RTR model.
The black boxes simply unscrew and drop away, which is great. That on the power car contains a great shiny rough-cast block of a soft but very dense metal. It couldn't possibly be lead - the notoriously rigorous Chinese H&S regulations , tightly enforced by vigilant and incorruptible officials, would never permit that. But there's a lot of weight there and it needs replacing.
I've araldited in place the replacement castings, built up the fuel tank to a box and stuffed in some more lead - fixed with more araldite. I've also removed the moulded underframe exhaust pipe and silencer and replaced them with the equivalent MTK: it looks slightly better and every bit of weight helps . I've left the Dapol/Hornby moulded exhausts on the end - although there is no fat cylindrical section (filter? silencer?) on these, there isn't on the MTK castings either so there's no point in changing them.
The metal plate between the chassis and the seating moulding has been replaced with lead flashing to compensate for the considerable weight lost when removing the black box beneath. Electrical insulation tape has been wrapped round the edges to protect the wires from the trailing bogie which run alongside - I don't want any sharp edges cutting through wires from the pickups. One slight drawback to all of this is that the lead is not rigid and therefore the power car chassis is now a little flexible in a way that it wasn't, even when the seating unit is screwed back into place.
I've also filed down and refitted all the glazing along the sides to achieve a flush result. It was an awful lot of work, and I must admit that I'm now in two minds about the result, especially where the main side windows are concerned. It is not nearly as neat as I would wish, and it does rather shout "hand-made!" at you. It's more accurate, but I'm not confident it's a lot more convincing. I'm seriously thinking about leaving the main windows alone if I tackle my second, long-forgotten, 155 at some time in the future. The small windows in the doors would still need doing, but when surrounded by a very dark blue the main windows are much less obvious and the RTR finish is much neater than I can achieve. The Hornby Pacers, where the inset of the windows is much greater, and the number of windows involved much smaller , are another matter.
Further upgrading work on the ends involved fitting etched gangway plates robbed from an A1 Models 156 upgrade kit (I have all the necessary bits for a 156 in the Hurst kit someone on here sold me), and adding Hurst cast brass snowploughs. The projecting lugs on the latter around which you pour superglue gel need filing down a little to get the chassis to seat neatly at the ends.
One key upgrade, though a fairly simple one, addresses the problem that Dapol simply omitted the solebars and extended the bodyshell down to where the bottom of the solebars should be. The chassis clips inside as if this were an integral construction coach like a Mk2 - which it's not.
The traditional fix for this is to paint on a fake solebar, which is what I've done, using Tamiya masking tape and brush painted Revell anthracite - a useful "off-black". I also added lifting points over the bogies with scraps of 40 thou plasticard filed to the body profile (These actually now help to get the body off)
Roof aerial plates (A1 etch) have also been added. Snowploughs from Hurst Models brass castings (remember Hurst Models?) were deferred as I was hoping to get the unit ready for Blacklade's first show, so I could display multiple unit working with a 155 + 153 consisted.
However the 155 had other ideas and fought back at the last moment, stopping dead......