Tag Archives: Bachmann

Converting the Murphy-Bachmann 141 Class Diesel to 21mm Gauge

Denis Bates

 

The General Motors 141 Class diesel of CIE was introduced in 1962, and for over 40 years has been among the most successful of the Irish diesels.  So it was not by accident that Murphy Models chose it for their first foray into a completely designed Irish model (the previous Woolwich Mogul and the NCC Jinty were of course repainted versions of the English models).  So, although my main interests are in steam days, and particularly the BCDR, I couldn’t resist purchasing one, with a view to re-wheeling it to 21mm gauge and P4 standards.  The prototype is described and drawn in two of the model magazines: by Tim Cramer in Model Railways for March 1977, and by Shane McQuillan in Practical Model Railways for June 1986. The latter article describes also the building of one, from a kit by the Model Irish Railways group. Comparing the Murphy model with the drawings, I could find nothing amiss – except for the buffer spacing. The buffer centres should be at a spacing of 6’3”; on the model they are at 23mm (5’9”). I presume that is to match the spacing of other Murphy-Bachmann models, at English spacing.

I first determined that a P4 wheelset would fit between the bogie frames, and it does, just. My main mistake was to dismantle the loco as far as possible – this is not necessary, as the bogie frames can be levered off. They are similar to those of the Bachmann Class 20 diesel (described by Keith Norgrove at http://www.norgrove.me.uk/index.htm). A screwdriver is used to prise out the frames, which appear to be identical on the two bogies. The wheelsets can then be prised out of the bogies. Each wheelset has an offset plastic gear wheel, two brass bearings which are a push fit in the sideframes, and brass wheels with insulating sleeves. Measure the distance of the gear from the ends of the axles, before tapping out the wheels and sleeves using a small drift and hammer. The gear wheel can similarly be tapped off the axle.

If the model is to be converted to EM gauge, all that is necessary is to cut 2mm steel rod to the appropriate length, and put the gear and wheels on. Although there is a spline on the original axle for the gear, it seems tight enough on a plain rod (a smear of loctite could be used to anchor it firmly). To keep the axle laterally in place, two brass sleeves, or an appropriate number of washers, should be added between the gear and the bearings (or between the bearings and the insulating sleeves (see figure). For conversion to P4 and 21mm, the original brass wheels can be used, but have to be turned down to receive P4 rims (these are obtainable from Alan Gibson on special order). It is also possible to turn down the existing rims to P4 standards. For those without a lathe, it may be possible to purchase P4 wheels to suit. Before finally inserting the wheel sets, the pickups need to be adjusted so that they bear on the backs of the wheels. On the Bachmann wheelsets, the hub projects further out than the rim, and does not fit easily between the sideframes. However, the insides of the frames can be filed out (about 0.5mm or more) to give clearance. I used a cylindrical dental burr to do this, held in a drill press, and hand held the frames. Once finished, the loco ran just as well as it had done on 00 track. Now to try it on Adavoyle Junction, out of period though it be!

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“Nearly Irish”

Colm Flanagan

 

With the arrival of our first really good RTR Irish diesel, and coaches to match by the time this is published, the thoughts of some modellers are beginning to consider whether a steam loco might be viable as a commercially produced model.  If this were so I’d vote for the LMS NCC/UTA/NIR/RPSI Class WT (Jeep) 2-6-4T.  Will it happen; who knows? But in the meantime, are there any ways of getting something like it?  The similarity between the ex-NCC 2-6-4T and its British mainland counterparts has often been remarked upon and in the last few years we have been favoured with Hornby and Bachmann giving us just about all the variants of the LMS/BR “equivalents.”  Over the past few years, as readers of New Irish Lines may remember, I have been building a chopped version of the Hornby Fowler tank which most folk have been very kind about.  New models of the UK 2-6-4Ts have appeared since then, so I thought it might be of interest to do a “state of play” round up, specifically looking at which, if any, of these is closest to the “Jeep.”  There were five variants (that I know of) on the theme:

  1. The original Fowler tanks produced for the LMS.  Modelled by Hornby in the 1980s and ’90s.  A super-detailed version was produced more recently; a renumbered version of this is due this autumn.
  2. Some later versions received side window cabs.
  3. Stanier then produced a variant with a taper boiler, whose dimensions were otherwise the same as the Fowler.  Hornby have recently produced this one.
  4. Fairburn produced a similar locomotive with a slightly shorter wheelbase.  Modelled by Bachmann – still available.
  5. BR produced a standard 4MT tank rather similar to the Fairburn; Hornby Dublo first made a model of this in the 1950s and Bachmann do a model which has been in their catalogue since 2002.

It was between the appearance of 4 and 5 that Ivatt supervised the building of the “Jeeps” – they were possibly designed by Stanier back in 1943 (according to JRL Currie) but building didn’t actually start until 1945.  The first 10 arrived in Northern Ireland in 1946-47, the latter eight 1949-50 (50 was the last actually delivered to the NCC, the rest to the UTA).  So, we seem to have quite a bit of choice.

To begin the consideration, we have to bear in mind certain things.  All of the English locos had wheels 5′ 8″ or 5′ 9″ whereas the Jeeps had 6′ 0″.  The Jeeps had a smaller diameter bogie and pony truck wheel; all of the English locos had longer fireboxes/boilers and shorter bunkers than the Jeeps.  With the exception of the Fowler (1 and 2) they had different wheelbases, mostly between the front pony truck and leading drivers.  Therefore for total accuracy, build your own, or wait in hope for a scale RTR model.  Anyone following either of these approaches may read no further!

Next a major issue: by the time the Jeeps were built, taper boilers were the norm in England, but the Jeeps had a parallel boiler, as it was decided to use the same one as had been used for the earlier mogul tender engines.  On the face of it this rules out all variants except 1 and 2.  However, let us assume that you don’t want to carry out major surgery (and it would be major: I certainly haven’t even tried it!)  Taking the most modern engine first:

The BR Standard 4MT:
Built some years after the Jeeps.  This has side window cabs and a built up bunker which looks reasonably “Jeep-like.”  Also, the front cylinders are high and angled, again, quite good.  This is the only one to have the correct pattern of two steps to the tank undersides, although an early drawing shows the single step on No. 5, the first to be delivered.  This is of course an error as any photographs will quickly show.  There is a continuous footplate, though the Jeep had a cutaway.  However, the “look” of it (whichever version, Dublo or Bachmann, you use) is just too “heavy” in my eyes and that, coupled with the points above, rules it out.

The Fairburn:
The first of which were built in1945, shortly before Ivatt took over as LMS loco superintendent.  Fairburn died suddenly in October 1945 and was replaced by H G Ivatt.  As the BR version has side window cab and bunker, these look more angular than the BR one.  This loco also has a cutaway front footplate.  It has a single step under the side tanks.  Allowing for the points made above, it looks not unlike a Jeep to my eyes.  One slight issue is that there is a definate “kink” in the top of the side bunkers, though this isn’t really noticeable on the model.

The Stanier:
Built in the 1930s.  Side window cab bunker, similar to Fairburn, but with a continuous footplate, similar Fowler frames and the cylinders are at a lesser angle to the horizontal.

The Fowler rebuild:
Built in the late 1920. The good news!  Wheel base dimension is accurate.  Side window cab (though see above); no cutaway on the footplate, and cylinders as Stanier design.  But it has a parallel boiler which is correct, and it’s a bit long overall (as is the original).  If you contemplated doing a small bit of chopping this would get you near with cutting away the footplateand altering the profile of the tank underside, neither a big job.  The bad news: this is the one variant nobody currently makes!

The Fowler original (1926-27):
As above but the cab has no side windows, these have to be cut out and new window frames made, which is what I did on my own conversion; I also cut away the cab and this lengthens the bunker, then did other things, etc. to produce my engines, which take it out of this survey’s remit.

So my conclusion?  If I wanted something “Jeep-like” with no work, just a repaint job essentially, I’d get a Fairburn.  For a little extra work, alter the bunker underside, fit a handwheel to the smokebox (a very Irish thing, that) and repaint, even better.  If you are prepared to do more, than I reckon the Fowler is the better bet to start from.  You’re still left with some compromises of course, but so far that’s the best I’ve come up with.  And if Murphy Models or someone else decides to go for the first proper scale Irish RTR steam loco, my vote goes for a Jeep.  In UTA days they were found on every line still open, they took excursions to Dublin, and in RPSI ownership No. 4 has travelled everywhere in Ireland and still operates today.  The “universal” engine, in a way its builders would never have foreseen.  It could look equally at home with a rake of Cravens coaches of any era, NCC/UTA coaches of Midland style, or the RPSI set.  Of course, if this superbly detailed ultra-accurate WT appeared then I might have some secondhand conversions for sale on eBay!

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