Stourpayne Marshall - 7Fs
7Fs are vital for any representation of the S&D so plans have long been afoot to make sure the layout can call on a number of these fine, versatile locomotives.
Shown above are a Bachmann example, and a DJH one of which more anon. Two more are in the works - another Bachmann, and a large-boilered DJH.
Back when I started thinking about the layout, the Bachmann model was a distant gleam in the future, with the two main options besides scratchbuilding being
the DJH kit and the Gibson one. I think I may have seen a resin kit for the 7F body on a Hornby 8F chassis at some point as well.
I discounted the Gibson one as it wasn't in production at the time, and to be honest an all-brass loco would have been a bit of a stretch for my skills. But I'd
built a couple of DJH locos so I thought might be able to make a fist of their kit, even though I'd never built anything with valve gear or more than three
axles!
Fate intervened, however, with the option to buy a ready-made small-boilered 7F on the second hand market, along with an unbuilt kit for the large boiler
variant. The unweathered loco in the above shot, 53808 (but we'll come to that!) is the DJH one and it turned out to be built to what I'd call a reasonable, if
not brilliant, standard. The smokebox door was crooked, and the front bit of the tender isn't square-on with the sides. Other than that, though, the main
body and cab were OK, and paint job was fine. Running was a bit of a mixed bag, unfortunately. Initially it wouldn't go through the tighter route of Peco
curved turnouts, due to insufficient side-play. But this turned out to be easily resolved by adjusting the main gear's position on the axle, which was too
far over to the one side, effectively giving the loco lots of side-play in one direction but not much in the other. Pickups seemed OK. The loco didn't run
all that smoothly, though, and I wasn't happy with the Portescap gearbox/motor as supplied, which was horribly noisy. I fitted a decoder, ran the loco for
a few days, then decided I just couldn't get on with the Portescap's constant graunchy whirring. Luckily, I had a DJH AM10 gearbox going spare. I managed
to swap it in fairly easily without having to remove the motion bracket or cylinders, aided by the drive being onto the third axle. If it had been onto the
first, it would have been a far tougher job. I was pleased to see that the running was now much quieter and steadier. But with that improvement, I became
aware of a tight-spot which had been masked by all the other issues before. It looked as if one of the crosshead spindles hadn't been trimmed to length
properly, with the result that it was clonking the front of the cylinder! To cut a long story short I managed to shorten the spindle and was pleased to see
all but a small residual tight-spot which I haven't yet diagnosed, but which disappears above an absolute crawl. It might be slight non-concentricity of the
gear, rather than anything to do with the motion. But I must admit, were I building this loco myself, I would have hoped to eliminate both these problems
before continuing. However, the main thing is that the loco will now plod around with a nice goods train which it couldn't do before. I also added extra
pickups to the front bogie, eliminating a slight tendency to stall on occasion, probably due to an over-rigid chassis (again, with mine, i open out one or more
of the bearing sets to allow a tiny degree of axle float).
So we've got another smooth-running 7F to join its Bachmann stablemate? Well, not quite! As far as I understand things, 53808 was one of the later series of
locos which were initially fitted with large boilers, of which some reverted to the small boiler, but always with the left hand drive. However, the DJH boiler casting
is for the earlier, right-hand drive series, with the associated plumbing on the right side of the boiler. At the very least, then, again as I understand it, 53808
is an inappropriate number, so I've tentatively earmarked 53801 for this loco. But the fun doesn't end there, because the reversing lever has been fitted to the
left hand side, not the right! Unfortunately, then, it isn't going to be a case of simple renumbering, but some remedial work on the body itself. How easy it will
be to remove and re-fit the reversing lever remains to be seen!
These problems aside, the DJH model sits quite nicely next to the Bachmann one, I think. The DJH boiler details are poorly defined, and there's a slight different of
opinion about the degree of drop on the front of the running plate, with the Bachmann one being more accurate, but it's surprising how a smooth-running mechanism
can make a model go up in one's estimation. I look forward to sorting out the details, renumbering and weathering this one. Then it'll be onto the large-boilered 7F,
which Bachmann have never done, which should add a bit of variety.
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