Atlantic's works: Portable layout - Scenic details next

[Hatfield Shed]

I don't yet know Mick. The print has been shaped so as to fit over, and conceal, the circuit board (and chip if fitted) on the front of the underframe unit...

That's an aspect for the designer to give thought to. I would hope that any likely customer would be able to rearrange the wiring and decoder socket for minimal intrusion into the coal space, and that representation of the bunker slope and sides only down to the location at which they might foul the installed gear on the tender chassis, would be preferable to a bulky concealing cover. Leave the modeller to make their own decisions on concealment of 'what lies beneath' by installation of a 'bunker floor' at a location of their choice.

(Side note. One of the major downsides of the DCC sound gimmick in RTR OO is the damage done to tender models, which all too frequently no longer have a fully modelled coal space.)

[Atlantic 3279]

Since one of the ridiculously flimsy cores of the four wires to the circuit board has already snapped off as a result of normal handling during the conversion process, and as I won't be using DCC, I'm tempted to eliminate the circuit board completely, leaving scope for a proper bunker if I can be bothered to build one. Although there are no tender pick-ups in the C-class chassis units as supplied, I might retain the wiring through to the tender in case I wish to add tender pick-ups.

[Atlantic 3279]

Following private communication, Paul has suggested that I might post these images, showing the way I've inserted 1.5mm square brass bar into the outer edges of the recesses under the running plate, plus some carefully cut linking channels. Superglued in place this has given me more confidence in the plate's straightness and rigidity. I did consider a full length slot, but I did not really want to remove and then re-attach the middle steps, but I've taken the reinfocement as close to those as possible and it seems to be sufficient.
Obviously, the slots had to be cut to a sufficient and even depth, and cleared out well, before the bar was glued in, otherwise a further cause of distortion would be introduced. I drilled chains of blind holes and then used a combination of knife, scraper and abrasive wrapped around a small straight edged piece of metal to take out the remaining material. There was no access for a normal miniature file, although I could have tried a riffler file.
Equally vitally, care has to be taken when holding the bar and the printed material tightly together while runny super glue is being applied and allowed to creep in to the joints, as distortion can be caused rather than corrected if you don't check what is going on...

[Atlantic 3279]

Who remembers clackers, and have the painful knuckles been forgotten half a century on?

Okay, well the topic is not quite clackers, but clack valves. After studying photographs in Hoole's NER locos book, and measuring a drawing in the same, I reckoned that I ideally wanted the main upright cylindrical part of the valve body to be about 1mm or slightly more in diameter, with the lower flange 2mm diameter. I haven't quite managed that using the bits I could find, as I had no brass tube slimmer than 1.5mm and crankpin washers almost 2.5 mm diameter were the best I could find for the flanges. What I've actually used is a strange mixture. The feed pipe and the supporting stem that runs through the whole lot is 0.7mm brass wire. The rounded top of the main cylindrical part of the valve, and the inlet pipe to the boiler are represented by an old Bachmann handrail knob, which was big enough to stand careful drilling out to take the 0.7mm wire. Below the knob is a short piece of the 1.5mm tubing, also drilled out to take the wire, and then the Markits washer at the bottom. I've enlarged the flange of the handrail knob to about 2mm diameter by adding a collar of plasticard, in order to make it look a bit more like the flange on the side of the boiler.

Too big? I won't tell anybody if you don't.

The shiny aluminium tape reveals that I've been tinkering with the position of the first boiler band to suit my preferences too.

[Atlantic 3279]

You may not believe it but I am trying to keep this project simple and brief by avoiding work that doesn't seem absolutely necessary. Hence, while I am fully aware that the style of brake arms and brake shoes on the chassis is wrong for a J21, I did check to see if there was a way to fit external pull rods to at least suggest the correct gear for the type of loco I'm aiming to portray. I reckoned there was just enough room to do it, without fouling the sweep of coupling rod bosses and crankpins.
I started by pulling the incorrect hopper sand boxes and the pipes feeding the middle wheels off the frames. 0.7mm brass wires 30+mm long were then slotted through the slightly enlarged pre-existing holes in the brake shoes. The rear cross-wire had to be bent slightly to pass around the bottom of the chassis.

The representation of each of the pull rods was another length of 0.7m brass wire, but in this case with flat faces filed onto opposite sides. I would have used flat strip if I had any. I limited the amount of filing for fear of work-hardening the wire and making it prone to fractures, especially with all of the file scratches on its surface. I wanted to be able to bend it to shape after soldering it to the cross-wires.

I initially soldered one pull-rod to the undersides of the cross wires on one extreme side, well away from the plastic brake shoes, arranging to have one of the flattened faces of the rod showing on the outside.

I thought about making the gear in split-down-the-middle form so as to avoid any possible electrical shorts, but I wasn't sure that the complication was necessary. I decided instead to try to space the pull rods out sufficiently from the wheels to ensure that there was no contact even with the generous side-play for the wheels in this chassis.
I found that if I laid the chassis on one side, the one already equipped with a brake pull rod, and put some packing under the motor, the crankpins on the "lower" side pushed the wheelsets up nicely to the "upper" side, while the incomplete brake gear fell to the "lower" side. That appeared to produce the sort of clearance that was needed between the pull rod and the wheels on the "lower" side. I then put some card spacers in position on the wheels of the "upper" side so that I could solder the second pull rod in place, suitable spaced from the wheels, using great care to avoid over-heating the the brake shoes which this time were very close by...

I found that in fact I needed card spacers between the pull rod and wheels on the lower side of the chassis too, otherwise there was a tendency for the cross-wires to move up through the holes in the brake shoes, closing up clearances on the lower side.

Even then I didn't get things quite right first time around. There wasn't quite enough clearance. I had to release the second pull rod and insert two thicknesses of card spaces on the upper side before re-soldering the joints. The excess length of the cross-wires was then trimmed off and any excess solder cleaned up.

The parts of the pull rods to the rear of the rear cross-wire needed to slope upwards slightly to emulate the real thing. A tweak with pliers created the necessary bend, but the sloping portions of the pull rods then fouled the rear crankpins and bosses slightly, so I made the sloping parts of the pull rods divergent too. The rear ends were turned upwards and tucked out of harm's way behind the rear steps.

Some fiddly drilling of holes, careful bending of wire, and off-piste use of a medium length handrail knob has also allowed me to add some of the missing pipework for the Westinghouse pump, and the operating rod for the front sandboxes. My chosen loco didn't appear to have the cup-type lubricators on the sides of the smokebox, so that saves me a job, and I'm not fitting grab rails above the middle steps - for reasons that I won't mention.

[manna]

G'Day Gents

Very nice

manna

[Woodcock29]

Hi Graeme.
I like the progress on the J21. I'd be interested in one myself except for the fact I bought a nice built Alexander kit from a mate a few years ago which I still need to make some tender mods to.
I've been studying the Oxford J27 I got recently and have decided its quite possible to convert it into a superheated version which will be more suited to my fictitious southern area LNER layout. Because the boiler unit can be easily detached from the footplate and front sandbox/splashers it should not be too difficult to extend the smokebox forwards. If I can't easily remove the smokebox front/door which is a separate fitting but glued well in place, I will scrap that door and simply glue plastic card layers to the front and shape them to match the curves of the smokebox. I still have some of your NE style smokebox fronts that I used on my Thompson O1 which I can cut a door out of to replace the destroyed one as the door diameter is the same. Of course I'll have to move the chimney forward but I should be able to remove that, fill the likely hollow in the smokebox and add a taller rim and possible a 'windjabber'. I will have to modify the tender frame cutouts to the parallel style and modify the coal rails - that bit being the easiest. Unfortunately I have no time at the moment to pursue this but maybe later in the year or next?
Andrew

[Atlantic 3279]

Thanks to both of you.

The separable J27 boiler sounds like good news for conversion purposes. I fancied a J27 myself but I did not want to add another job to my list at this stage. Had I done so, that would no doubt have ensured the future introduction of a ready made superheated version.

[Atlantic 3279]

Prompted by earlier comments and suggestions from Hatfield Shed and Mick B, I've been making use of the day to study various photographs and drawings in Hoole's book showing NER tenders or parts thereof, and trying to evolve a simple, viable, inexpensive plan for improvement of the J21 tender print in respect of bunker and toolboxes. It seemed a bit too warm today for another series of energetic outdoor activites anyway...

With the "plan" loosely in mind I decided to try it out on the slightly distorted original tender print that Paul subsequently and very kindly replaced for me. I began by drilling a hole in the front of the raised cover for the circuit board / chip socket, and another one at the base of the bulkhead in front of the bunker slope, then inserted the blade of a piercing saw and cut out the raised cover.

I also filed away the central portion of the material that had extended down below the base of the bunker slope.

[Atlantic 3279]

Those first alterations cleared some of the space needed for a better representation of the bunker, as well as allowing the DCC socket to be unscrewed from its mounting pegs, turned around with care so as not to snap any of the wiring (which I already had to repair once), and slotted into the printed body above reinforcing ledge in the rear of the tank.

The removal of material under the bottom of the bunker slope was necessary to allow the body to fit on the underframe without pinching the re-located wires between the two units.

[Atlantic 3279]

My next move was to drill a straight row of closely spaced 1mm holes right across the front face of the tender, so that the bottom edges of the outer holes were flush with the tops of the visible parts of the tank front arms. There was no safe access that I could see for simply cutting a straight line with a saw instead. I could however use the piercing saw to cut around the edges of the top area on which the toolboxes sat. I cautiously broke free the toolboxes and their base and put the removed piece aside, carefully, for later attention...

I had retained the front coal plate, which seemed as if it might be correct, and which helps to keep the side sheets "in gauge". After removal of the tool boxes I cleaned around the edges of the hole with a file, leaving the front lip at the bottom of the upper front coal plate but thoroughly cleaning out under the ends / corners of the plate.

[mick b]

Much better looking !! There should be a approx 3mm gap at the bottom of the Coal plate as well .

[Atlantic 3279]

The representation of the coal gate between the tank fronts is very thin and fragile. You'll see that part of it at the top broke when I was simply trying to gently drill it. I'm not sure it would stand up to having a shovelling gap cut at the bottom, unleee I thicken it with a layer on the rear first.

Anyway, after removing the original material I cut a piece of 0.75mm thick plastic, 45 x 26 mm and filed a long taper on what was to be the under-side of the rear edge. I also marked out ready for cutting a slot 32 x 12 mm centrally at the rear.

I checked that this would slide into position thus:

I then removed the new piece again and cut out the rectangular slot that I had marked. Although I knew I wasn't making the base of the new bunker low enough, I decided to minimise work by simply matching the level of the bottom of the rear slope. I therefore cut bunker sides, again from 0.75mm plastic, 8mm deep, 42.5mm long at the top edges, 30mm long at the bottom edges, with an 11mm long portion of the top edge removed from each towards the front. That final feature allowed me to fix the top edges of the bunker sides within, rather than under, the edges of the slot in the top plate.

I kept the front of each bunker side piece 2mm back from the leading edge of the top plate, so that the top plate could still sit on top of the remains of the original tender front. The piece I had cut out from the top plate, trimmed down to a length of 30mm was then fixed to the base of the bunker sides, and a small rectangular piece inserted to complete the front of the bunker, adding strength.

N.B. SEE LATER FOR AMENDED BUNKER DIMENSIONS
https://www.lner.info/forums/viewtopic. ... 67#p142367

[Atlantic 3279]

The completed new bunker shape is still a slide-in fit under the remaining upper front coal plate, in fact there was room for an additional strip of 0.75 mm plastic under that plate to make things a good fit.

I could have fitted replacement tool boxes but I decided to make best use of the existing ones, in improved form. After trimming away the remnants of the old base plate I added an overlay of 1mm thick plastic to the end of each toolbox to make each one 12mm wide. I made each overlay extend only 5mm back from the front edge of the toolbox. I then carefully cut off all of each toolbox to the rear of this new line, using a razor saw, thickened the tops of the boxes with an internal extra layer of 1mm plastic, and added new rear faces of 1mm plastic, making the new boxes 6mm front to back. The top rear curves were then filed in, and all joints or edges tidied up.

Here is the loosely assembled trial piece (dark grey) compared to the replacement print (light grey) which I can now consider altering to accept the new parts.

[Atlantic 3279]

In the final images above, you'll see that the fronts of the toolboxes sit about 2mm back from the front edge of the new piece I've made to represent the bunker, the tank arms, and the toolbox shelf itself.

I've now received further advice from Mick B and I've had a look at My Hornby Q6 tender (which I should have done earlier). If I've understood or interpreted correctly, I now believe that I can make my representation of the tender front better still if I cut back the front edge of my new piece by about 2mm so that it exposes a short part of the open top of the coal space in front of the tool boxes, and gives an appearance as if the toolboxes were sitting on a simple shelf across the front of the coal space. That will mean that I also have to add some material at the sides so that the tank front arms still appear to extend back under the toolbox shelf.
At the same time, I may take the strengthening piece out of the front of the new bunker to create enough space to stick a reinforcing layer onto the back of that flimsy coal-gate section of the print between the front arms of the tank. I can cut a shovelling hole at the bottom, although in this case it will actually be below the floor of my shallow suggestion of the bunker...