Scrap Tank, construction progress.

Construction of the chassis of my 7mm scale Scrap Tank is well advanced and the mechanism progresses smoothly under power along the test track in the studio, so a test run on the club layout in Carlisle at this stage might be a good idea. There is still much detail to add below the footplate which I will leave for a later stage of construction; meanwhile I'm looking into the possibility of 3D printing some components, particularly the sand-boxes and driving wheel springs and maybe the rivetted wheel balance weights. The coupling rods were made for me by WMI; the connecting rods I built myself. The gearbox is an ABC Mini7E mounting an M1833 motor. The footplate assembly is screwed to the frames through the front frame spacer; the rear frame spacer slots into a housing fastened to the inside of the back buffer beam.

Phosphor-bronze pick-up wires (0.5mm) are arranged to bear on the tops of the centre and rear drivers which will locate inside the engine's spacious side tanks; those that bear on the front driver have not been resolved yet. The left hand driving wheels are shorted by means of an 0.5mm p/b wire soldered between hub and tyre and slotted behind a spoke.

With the front driving wheels are in position, the axle screw is masked by the slide-bar/cross-head assembly and inaccessible. To overcome this the axle and its brass bearings is retained by a keeper rod soldered to a plate. The removable plate slots in place against the front frame spacer and is retained by a screw. 

Clearance between the chunky cross-head casting and the coupling-rod is minimal and much metal had to be removed warily from the rear of the casting and from the head of the protruding crank-pin screw to achieve free movement.  

HR 118 Progress

The chassis is separate from the superstructure, being held in place by a bolt, which engages with a nut hidden in the smokebox, a tongue and groove arrangement secures the rear. An ABC Gears Mini 7E with an M1824 motor and flywheel fits comfortably into the boiler which is cut away to accommodate the mechanism. Pick-ups are 0.5mm phosphor-bronze wires bearing on the back of the left-hand driving wheels, while those on the right are uninsulated. I'm working on a pick-up from the front carrying wheel too, which should further improve performance. There's a surprising amount of detail on this little engine and it won't be complete before its first trial outing on the the club layout in Carlisle early next month.   

The motor is supported on a cross bearing just behind the flywheel to keep it from resting on the axle.

Using an M1824 motor allows just enough clearance inside the cut-away boiler. A sand box will be mounted behind the motion plate.

Buffers are from Roxy Mouldings and are mounted high on the buffer beam, so the retaining nuts are too big to fit under the footplate and an alternative needs to be designed.

 

LNWR Precedent...Merrie Carlisle

 

Renewed Precedent Class, Merrie Carlisle, LMS 5050 in 7mm scale 

The engine is built in nickle-silver, without the aid of a kit, though the tender is a Gladiator Models product, to which I made a few improvements. It is intended to finish the model in early LMS red, Merrie Carlisle being one of only four of this class to be turned out in full red passenger livery. When the engine first appeared in its new livery it carried number 5050 on a smokebox plate and retained its original socket lamp-irons. The Bill Finch Portfolio of Locomotive Details, published by the LNWR Society was an invaluable help in building the model. The only kit I know of for a Precedent is a Mercian Models product, which may no longer be in production.

Precedent chassis and mechanism revealed

Power is provided by an M1824 motor and ABC gearbox, mounted on the front driver and fitted with an MSC flywheel. I could have fitted a more powerful M1833, though there would not have been room for a flywheel. I prefer the smaller motor/flywheel set-up, which greatly enhances the engine's running qualities. Pick-ups are phosphor-bronze wire wipers on the left-hand wheels; the right-hand wheels are shorted by hidden wires. The front carrying wheels are from Slater's, who do not produce suitable Precedent driving wheels, those I used were supplied by JPL and may not be available now. 

Allan's straight link motion, simplified by the omission of the drop-links, fills the gap under the boiler. The valve rods pass through a gap in the motion plate. The sand boxes, which flank the motion plate, are filled with yellow Milliput.

The inside motion unit removed.

The tool box castings have been detailed and display how they were fastened to the tender top. 

Under the tender.

The water pick-up apparatus has not been included under the tender though the double brake pull-rods have been modelled fully. Note the tender buffers, which really work, being sprung behind the buffer beam. 

The Crew.

The loco crew are from my own sculpture and are cast in white metal in my workshop. Both figures are mounted on thin sheet metal bases and secured to the deck with double-sided tape. The fireman stands on the tender fall-plate, his base is made from scrap chequer-plate. The poses of the crew are designed so they relate to both the engine and to each other. They were designed as the model progressed and are an integral part of the model, by no means merely an afterthought.

The brakes are a tight fit.

A busy cab interior.

I built the cab interior with the help of castings from Laurie Griffin's range, most of which were modified in some way to suit a Precedent. I used Bill Finch's drawings for reference and don't think I left anything out. The roof, which is attached to the inner skin of the spectacle-plate, can be lifted off, which allows the back-head to be removed too. The spectacle-plate is double-skinned so the window glazing simply slips between the inner and outer skins. The prominent reversing wheel would have been better as a nickle-silver casting to approximate the steel original, but I could only get a brass one, I'm sure it'll look fine with the rim buffed up.

I heard recently that the "Master" himself, James Beeson, painted his reversing wheels red!

HR 123 Loch an Dorb.

Loch an Dorb, from the Gallic meaning possibly Loch of the Minnows or more likely Loch of Troubles. The model is complete now apart from coal in the tender which I have in hand. The basic colour is Precision P727 which is now no longer available, I only have enough left for touching up now. Etched number plate, name and buffer beam transfers are from Guilplates, the latter are no longer available either. Footplate crew are my own sculpture, designed for this particular engine and now available from Invertrain. 

The cab interior is as complete as I can make it, I took the details from the drawing in Peter Tatlow's "A History of  Highland Locomotives". The backhead casting and many of the small fittings are from LGM though both have been modified to suit. 

Cab interior and crew with the roof removed for a better view of the works.

 

The superstructure owes a debt to some specially commissioned nickle silver etches from Lochgorm Kits, the chassis however was scratch built. Wheels are cast and turned by JPL Models as Slaters have no correct ones in their list. Motive power is provided by an M1833 motor mounted in an ABC Gears Mini Gooch gearbox. Loch an Dorb's debut on the club layout in Carlisle will be much delayed I fear by the renewed Coronavirus outbreak, I won't be going up to the clubroom this side of Christmas and probably for some months after, neither will I be able to photograph her in a realistic setting hauling a train, she'll just have to wait.

Jones Tank bogie rebuild.

HR Jones Tank No. 58 after her repairs

At the February Running Day on the CDOGG layout in Carlisle my Jones Tank, which was built some time ago did not run at all well, in fact she failed to negotiate the circuit at all. I thought it was partly a problem with the front bogie and partly due to the vagaries of the track, particularly where the lifting flap provides a testing unevenness, which has been the ruin of the pretensions of many a poor engine. My misgivings about the track were however unjustified in this case as examination of the offending bogie running on my test track at home highlighted the fact that the rear wheels were not even revolving! The problem proved to be entirely a bogie malfunction. Closer investigation showed that the frames had somehow expanded and were actually breaking away from the horizontal stretcher and locking the back wheels. There was a good deal of lead weight glued into the bogie between the frames and I could only surmise that, depite my using Araldite epoxy glue, expansion of the adhesive was somehow to blame.

The engine started life as an aged Jidenko/Shedmaster kit, described by Laurie Griffin himself as "a difficult kit" and difficult it is, nearly impossible actually, without a great deal of modification and improvisation. The bogie frames were, on examination, found to be only 0.45mm thick, too flimsy for frames really. In addition, the mudguards on the front bogie wheels had always been a problem, the restricted clearance causing them to foul the cylinders and front buffer beam. Though this did not result in an electrical short circuit, as the wheels are insulated from the mudguards, it did not improve the engine's running characteristics. I resolved to simply scrap the old bogie and build a better one and see if I could improve clearances at the same time.

The mudguards are clear of the cylinders now though it's still tight.

I cut the new bogie side frames from 0.7mm nickle silver and built the bogie solid, without compensation. The earlier version had enjoyed the complication of hornblocks for the rear wheels to slide in, which I decided to scrap in favour of simplicity, relying on the central pivot of the bogie to provide articulation in all planes. I omitted most of the lead weight, adding only a modest amount this time. I was able to re-use the mudguards, though I remodelled them as tight to the arc of the wheel as possible and though I probably managed to pinch less that a millimetre, it made all the difference and the rebuilt bogie ran visibly clear of the buffer beam and the bottom of the cylinders. I made new guard irons, bending them and their support from a single strip to replace the earlier multi-part lash-up, not only providing a more robust solution but also an improved appearance.

The engine runs well now, at least it does on my own test track in the studio, taking the 6ft radius curves in her stride. An ABC Gears' Mini Gooch gearbox with an 1833 motor and flywheel, which I deem essential if space allows, ensures smooth running.

My aim when building a locomotive is that it should perform well in a "club layout situation" and these repairs should ensure that it does just that. However, due to the ongoing deadly virus crisis, her test run on the club layout in Carlisle is postponed indefinitely...

Rebuilt mudguards and guard irons, note clearance under buffer beam is tight.

LNWR Precursor Tank

LNWR Precursor Tank No.44 built 1909.  3' 3" bogie wheels, exterior sand boxes and Bowen-Cook buffers.

Pete's Precursor Tank was built with the aid of a Dragon Models set of etches and the brass castings that come with the kit though without any of the white metal fittings supplied which were replace by components sourced elsewhere or by scratch building, an example of this being the smokebox door. Construction is complete apart from the cab interior which awaits delivery of an LGM brass backhead casting. There has been a good deal of improvement made to the basic kit and additional work has been done using contemporary photographs as reference to ensure that all exterior detail is included in the model. The basic inside motion parts from the kit have been fitted, viewed from the angle of the photo the slide bars are just discernable in the gloom between the frames.

The engine is powered by an M1833 motor mounted in an ABCGears gearbox which is mounted upright on the rear driving axle. Current pick-up is through wires bearing on the treads of the drivers and the rear of the bogie wheels on one side of the engine; on the other side the wheels are shorted by means of a wire inset behind the spokes. Slaters' wheels are used throughout, the axles run in brass bearings which slide in slots in the robust 0.7mm side frames. The upright motor leaves no space in the boiler for a flywheel, however the running qualities of the model were more than acceptable when she ran on the Carlisle club layout last Saturday.

The cab front is double skinned which allows the inner skin to be removed at this stage for detailing. The backhead and all its attendant fittings and pipework will be attached to this inner skin, an arrangement that also facilitates glazing at a later stage. Similarly at this stage the rear bunker assembly can be removed to allow access to the cab though later this will be soldered into place; the roof will be soldered on too as this will add strength to the structure. Nevertheless the large cab side cut-outs, generously proportioned rear windows and hinged opening doors will ensure that the cab interior detail remains much in evidence.