Mainline J72 to J71

[rowanj]

My layout could really use a J71, which were common sights along the "big brother" J72's on Tyneside shunting and trip works. No doubt many folks used the Mainly Trains conversion kit when it came out in 2005, and lamented its' passing. I recently caught up with the fact that Wizard Models had acquired the range, so ordered a kit, along with the J72 detailing pack. This latter is a bit of a misnomer, as it is essentially "only" an etched chassis kit with an etched cab interior.

 

Cheap J72 bodies are reasonably easy to obtain - mine was the cheapest at the time. Ideally, I would have bought a black one as I model BR-period . 

 

Their are a few major and quite a few minor differences between the J71 and J72. The chassis overall wheelbase is the same, but the wheel spacing is slightly different. more importantly, the J71 wheels at 4'8" are 6" larger than the J72.  The MT chassis' accurately reflect the wheel spacings of the 2 classes.

 

On the body, the J71 has larger splashers in order to accommodate the bigger wheels. New splashers are on the etch. In addition, the J71 bunker is 6" shorter than the J72 as modelled by Bachmann. The first 20 J72's also had the shorter bunker, and If this works, I'll probably get another body to produce a short-bunker J72 on the MT J72 chassis.

 

The cab is empty on the body, so a floor and brake standard is included in the kit. I will try to find a backhead and see what else may be fitted in the cab as the job progresses. Also included is a balsa plug for the boiler bottom,  a set of Alan Gibson LNER tapered buffers and a smokebox dart,.

 

The photos show the body with the bunker cropped, buffers and coupling removed, and splashers cut away. A perusal of Yeadon will identify what else needs to be removed before construction/re-construction commences.

 

John

[Pebbles]

I think its called a "Till roll". Its the plastic insert which receipt paper it wound around; ask at your local shop. Generally in the region of 14.8mm to 16mm in diameter, and far better than balsa plug for the boiler insert.  

[Daddyman]

I did a J72 recently. I wanted to have the correct shape to the tank fronts and have never been convinced by the idea of filing them out with the boiler in situ - the boiler seems to end up scarred. Instead I cut the boiler out of one body, sawing behind the smokebox, being careful to preserve the tanks and smokebox, but not worrying about wrecking the boiler (the cab is removable to facilitate getting the saw in). I could then get in to shape the tank fronts on the first body. I then cut the boiler out of the other body, not worrying about damaging the tanks or smokebox. I then used part of the first (wrecked) boiler to represent the missing part of the boiler bottom on the second. 

 

I also used the steps off the second body, cutting them off with a bit of valance - that bit of valance then being filed flush with the step backing plate and then glued inboard of the valance on the first body. This had the result of moving the steps inboard a bit to make them look better, and allow me to represent the brace on the front step; it would also allow you to run steam-heating or vac. pipes down the valance behind the brace. I know etched steps are available but I was on holiday and had none in my parts box.

 

I did other sundry jobs - scratchbuilt s.box dart, sanding gear, and blower valve on the LHS of the s.box, with the control rod represented by 0.3mm wire inside 0.5mm tube. This was an ebay rescue so I'm not sure of the provenance of the chassis. It had the early brake gear so I scratchbuilt new cross members. It came with the hideous Romfords, but I covered the nuts with 3.5mm discs of 5 thou brass, soldered to the end of a tube and shaped in situ, then removed and glued over the wheelnuts. 

 

The loco was for my dad and he's not particularly worried about detail, so I just went as far I had to so that I wasn't too annoyed looking at it. With my J71 I'm going further, using the MT kit: replacing the footplate as the Mainline moulding is awful, particularly the thick edge of the footplate; replacing the boiler with 16mm tube; and replacing the s.box hinge straps with scratchbuilt ones - at least I hope so: my last three-hour effort failed! 

 

The Gibson buffers look nothing like ex-NER buffers - no turned ones do. The only option is Dave Bradwell. Or choose a loco with G/S buffers - that was what I did. 

 

Edited November 8, 2018 by Daddyman

[rowanj]

Daddyman

 

Thanks - the J72 looks nice. 

 

The Mainline/Bachmann body is adequate as a starting point, but needs a lot of work. Interestingly, the MT instructions say nothing about the need to shorten the bunker.The footplate needs "thinning" - I wont go as far as replacing it - but the rear buffer beam is much too thick - only the front buffer beam got the "sandwich", I have started to thin it down - I need to get it as thin as possible before attaching the MT etch. The rear of the bunker sits JUST ahead of the buffer beam.

[Daddyman]

I doubt MT knew about the bunker. I've only just heard it from Arthur K in a post a couple of days ago. 

 

I'd try to get rid of the rear b.beam entirely if I were you. By the time you have the MT plate beam on, added to the residual Mainline beam, it will be too thick to represent plate steel. This is another reason why I think it's better to replace the whole footplate. The time one spend faffing around on things like this, and thinning the edge down, one could have cut out a piece of N/S. It also makes attaching etched steps easier - they can be soldered to the footplate. 

 

Here's a picture of test work removing the footplate on a scrap body - you'll see that as you skim the footplate away from underneath, you are eventually left with a thin strip, which just snaps off, ensuring accuracy: 

 

[rowanj]

I'm well into the "destructive phase" now, I took Daddyman's advice and removed the rear buffer beam, leaving only a small lip to attach the etch replacement, which I may actually finish off soldering to the chassis. The breathers on the J72 tank tops were not fitted to J71's, and if they had cab doors, I've yet to see a picture of them closed. I damaged the coal rails when shortening the bunker, and I'm not convinced I can repair them invisibly, so am on a so far fruitless search for an etched version.

 

The chassis went together easily - all the slots were accurate, and , although I always use a Poppys Jig for chassis assembly, I think you would need to work hard to make a mess of this one.

 

Incidentally, for anyone modelling NER/LNER locos, David (Daddyman)'s posts are well worth following, as are Mike Meggison (Mikemeg)'s.

 

John

Edited November 10, 2018 by rowanj

[Jon4470]

Hi John

Following this with interest, as it’s something that I’ve thought about as a nice little project to use up a spare body shell that I have.

 

Can ask please what make of wheels are you using?

 

Thanks

 

Jon

[rowanj]

Hi John

Following this with interest, as it’s something that I’ve thought about as a nice little project to use up a spare body shell that I have.

 

Can ask please what make of wheels are you using?

 

Thanks

 

Jon

 

Hi Jon.

 

These are 18mm W&T , I need to check but don't think I have any Romfords, and cant get away with Slaters.  I'm probably going to use a Mitsumi motor in Highlevel Compact+ gearbox with a 45/1 ratio.  This will really be an inexpensive build.

 

However, for anyone looking for something more elaborate, the MT chassis is designed to be built compensated, and has EM spacers on the fret.

 

I have used the W&T wheels before, and found them satisfactory, though they are, of course, "universal", They are designed to fit Romford axles, and are tapped for Romforf crankpins. Because they have plastic centres, they are all insulated, and you need to get in and out quickly when fitting crankpin washers. Scalelink are very quick to deliver, but, like a lot of similar businesses, the owner is about to retire.

 

John

[Daddyman]

I can give you the back end of a scrap body if you want? Will include coal rails. Or if someone has built a Bradwell NE tender, they may not have used the 3-rail option, and might be able to offer you spares... 

 

If you want my scrap body, I won't be able to post it until next Saturday. 

[mikemeg]

This one for Daddyman, though the chassis on this is not the Mainly Trains offering. This is the High Level chassis kit for the J72, which does have the correct brake linkage for these later locos. I did two builds of this chassis for Chris Gibbons, to illustrate the conversion on RMWeb. This kit also has a pretty good representation of the inside motion of these locos  - the cylinder fronts, slide bars, crossheads, con rods and Stephenson valve gear. The loco also had  a scratch built bottom for the boiler, scratch built rear sandboxes, new tank fillers, all new handrails (including those at the tank fronts), new lamp irons (including the smokebox top one), a complete set of cab fittings, etc.

 

I took this photo before I fitted new footplate steps as the originals were, again, far too thick.

 

And, of course, this had a new smokebox dart and handles - wouldn't now show it to David, if it hadn't!!

 

The footplate is still far too thick and now, I would probably replace that. Anyway, I bought this body for 50p so it wasn't too bad a bargain!!

 

As for North Eastern tapered buffers, the best I have seen are Arthur's lost wax brass castings. They are spot on!

 

Cheers

 

Mike

Edited November 12, 2018 by mikemeg

[rowanj]

Mike - if you have a picture of the Highlevel  inside motion, I may have a go at some sort of representation. The chassis looks very bare under the boiler as things stand.

 

John

[jwealleans]

Check the B2B on the W & T wheels - one set of mine (can't remember if it was J71 or J72) were under gauge and I had to shim them out.

[ArthurK]

Just to illustrate my own J71, here is a view of a very early test build - way back in mid 2016. Like others of my test builds it in P4 gauge simply to check that I have the tolerances right for that and, since it is only a checkout build it has a rigid chassis.

 

The internals include only the slidebars but later I intend to bring out a detailing kit with more bits between the frames.

 

 

The first kits will dispatched this week.

 

ArthurK

[mikemeg]

Mike - if you have a picture of the Highlevel  inside motion, I may have a go at some sort of representation. The chassis looks very bare under the boiler as things stand.

 

John

 

John,

 

This is one of only two photos which I took of the 'innards' of the J72 chassis build. It's a little 'busy' inside there but, hopefully, this may give you the idea. It's probably the things between the motion plate and the cylinders which are the most important as the stuff behind the motion plate is largely hidden from view  by the side tanks.

 

Cheers

 

Mike

Edited November 12, 2018 by mikemeg

[rowanj]

I will have a go at some inside motion, Mike, but it wont look a patch on your effort - very impressive.

 

I wasnt going to start on the bunker yet, but found I needed to to check the fit of the body/chassis. Unlike the J72, the rear buffer beam on the J71 was a single plate, rather than the thicker sandwich of the J72 (and the J71 front). As there was nothing left  to glue the etch to, after I'd cut away the back bunker, nor was there the remnants of the very short platform behind the bunker back, I soldered the buffer beam to a piece of scrap etch which was then glued with epoxy . The glue join seems OK but the solder joint is failing. So, rather ahead of time, I'll solder in the buffers and the bar for the coupling and hope I  don't have to go back to it.

 

The second photo shows the body posed on the chassis, and I hope one can see already that it is distinctively different from the J72 , Since taking the picture, I have tweaked the rear brake - pictures are cruel but certainly point up errors which my eyes don't always spot in the flesh.

 

Edit - I'll take a better photo of the rear buffer tomoorow in better light - I hadnt realised how poor it was - apologies.,

Edited November 14, 2018 by rowanj

[Pebbles]

Have you considered soldering the buffer beams to the chassis?

[rowanj]

Have you considered soldering the buffer beams to the chassis?

 

That option would work too, I have, in the meantime, resoldered the buffer beam, soldered in the buffers and soldered the" croosbar" coupling, made up from 45swg wire, as suggested many moons ago by Tony Wright. It all seems solid. Next stage is to assemble the gearbox/motor to see what needs to be done to the etched cab floor. I'm hoping to be able to fit a backhead, though I don't have an NER one. However, even with the cab doors open, I think something which gives the effect will suffice for this conversion.

 

John

[rowanj]

The chassis is assembled, and I'll post a photo when the light is better.

In the meantime, I have a query about the handrail, or lack of one, on the bunker rear. Should it be there ?. Yeadon suggests the first 20 J72 with short bunker had no handrail, so I assume the J71 likewise. Rear photos are few and far between and I can't find any in BR days.Of the 3 in Yeadon, 2 have no handrail, and 1 seems to have a short NER bar.

 

On the subject of ignorance is bliss, I've been happily running 68744 for about 30 years. I now discover it should have a trumpet cover over the Ross pop valves.

 

Every day is a schoolday even 50 years after leaving...

John

Edited November 17, 2018 by rowanj

[ArthurK]

J71s did not have a handrail on the bunker rear.

 

ArthurK

[rowanj]

J71s did not have a handrail on the bunker rear.

 

ArthurK

 

Thanks, Arthur. That makes perfect sense.  The picture which I referred to is of 1797 pictured on p.13 of Yeadon 43A. Closer examination suggests a more traditional handrail/handrail knobs, and is quite short. But my loco shall go without.

 

John

Edited November 17, 2018 by rowanj

[Compound2632]

Iain Rice did a Mainline J72 to J71 (or E1 to E, if you prefer) conversion with, I think, a Perseverance chassis, in a very early MRJ. 

[rowanj]

Iain Rice did a Mainline J72 to J71 (or E1 to E, if you prefer) conversion with, I think, a Perseverance chassis, in a very early MRJ. 

 

The Mainly Trains kit, now with Wizard Models, is an Iain Rice product, as is the J72, The "problem" with both locos isn't the quality of the kit - it's the variety of detail between individual locos. This , of course, isn't really a problem, other than the difficulty of getting a photo of both sides of a particular loco to suit a location - if that sort of thing is important. The advantage is that I can have a couple of locos of the same class where the detailed differences are quite significant. For example, my next J71 will be vacuum fitted, and my next J72 vacuum fitted with a short bunker,

 

John

[Compound2632]

it's the variety of detail between individual locos. 

 

Always model a class member for which there are no good photos. Then you can't be wrong!

 

That MRJ article was a classic and led to a youthful dabble in P4 on my part, which didn't get very far.

[Pebbles]

I trust this hasn't been mentioned before, but not only no upper bunker handrail but as built no step. This last point is a slight problem as some short bunker J72s and J71s did have some sort of step these are evident in Yeadon's.  Examples are J72 8680 on page 85 and J71 1797 on page 13, this last engine also has a handrail located beneath the lamp iron.

[ArthurK]

J71s did not have a handrail on the bunker rear.

 

ArthurK

 

Sorry I should have added the qualifier "when built". What happened thereafter can only be gleaned from photographs and the very few show the rear.

 

ArthurK