Monday, 24 April 2017

A GSWR Timber Wagon

GSWR Timber Wagon

I built this little Scottish timber wagon recently from a Dragon Models Celtic Connections kit, it's now complete and awaiting paint and transfers. The wagon also needs a twin to make it viable as a load carrying vehicle. I thickened the wagon sides to a scale 3" and modified the brake gear on the etch to conform with that of a timber wagon rather than that of a pig iron wagon, which was the braking system on the etch. I also removed the raised lettering from the number and loading plates as I intend to design and print some improvements myself. The wagon floor is Plastikard planking mounted on the brass wagon bed. Length of the wagon over buffers is 120mm; weight is 175g. Though not an easy build, the wagon certainly looks the part and cries out for a mate to keep it company.

Wednesday, 29 March 2017

HR Passenger Tank

Highland Railway 0-4-4T Drummond Passenger Tank

I decided to build my latest project, a HR Passenger Tank, without the aid of a kit although I was aware when I commenced the project that there were two kits available for the engine... I didn't think that either would be of much help. Laurie Griffin's lost wax castings for this particular engine once again are proving to be indispensable however. I began construction at the end of February and these  pictures chart my progress. The engine is up and running and will have a test run under club conditions on the CDOGG layout at the weekend.

Much of the mechanism is revealed in this rear view.
Chassis and mechanism in close-up.

I've shorted out the wheels on the right hand side of the engine and rigged up wire pick-ups bearing on the top of the left hand side driving wheels, the pick-ups should disappear nicely into the front splashers and side tanks.
The n/s pick-ups are mounted on copper clad insulation board from where a wire leads back indirectly to the motor terminal. The motor gearbox is from ABCGears, it's a Mini 7S with an M1824 motor which will have to run without a flywheel as there is insufficient room for one. It's not the ideal motor-gearbox configuration, though as I had it in stock, it'll have to do.

Rear bogie top view, note guard irons tight behind rear wheels.

I added extensions to the LGM white metal bogie side casting for this engine from 0.4 n/s sheet, the rear guard irons are attached to these...mixed solder and glue construction. The centre hole is for the pivot which at the moment is un-sprung though I'm thinking about this. Wheels run in 1/8" bearings without compensation.

Rear bogie underside
The pick-up arrangement can be seen in this view of the bogie underside. A detachable wire screws to the CCIB and leads to the motor. The right hand side wheels are shorted out, one with a wire and the other experimentally with conductive silver paint, which seems to work well.

Friday, 27 January 2017

HR Loch Cab details.

HR Loch an Dorb cab details

My previous post shows the backhead before I opened up the fire hole and added the mechanism which closed the hole. I modelled the details from photos I'd taken in the Transport Museum in Glasgow of the Loch's near relative the preserved Jones Goods. It seems that the hole was closed by a baffle which was hinged from the top and operated by that ratcheted handle on the right. A hinged grille closed onto this from the bottom though I've modelled the grille simply as a solid plate as I'm not sure how I can represent a grille in this scale.

An oil can, which I modelled on an example on display in Glasgow, is positioned to hide a joint in a pipe on the left hand splasher top where a pipe attached to the backhead meets itself as it emerges from the floor and makes its way to the splasher top rendezvous. The gap is necessary to enable the backhead to be removed.

The slight gap between the roof and the cab front will disappear when the roof is fastened in place at a later stage.

The two locating holes for the crew on the floor and splasher top are hardly visible.

I might try a coloured LED behind the fire hole to give a warm glow effect to the cab, possibly even a flicker, but I need to experiment with this, I don't know if I can make it work yet.

Friday, 20 January 2017

HR 123 Loch an Dorb; construction complete.

Though the superstructure of the Loch owes a slight debt to a Lochgorm Kits "Aid to Scratchbuilding" etch the model could be said to be almost entirely scratch built. A fair number of LGM lost wax brass castings have been used and these are easily identified on the photos following.

Showing the arrangement of the brakes and brake pull rods. I've simplified things under the tender, there was more to it than this!

The Jones Goods and the Lochs ran with identical tenders so I took some of the details of the tender front plate from the example on show in the Transport Museum in Glasgow. Note the bi-fold doors to the tender with a cut out on this side for the tablet catcher. 

Vaccum pipes always present me with a problem, here I've used n/s rod with the bend from a lost wax casting and a spring to simulate the hose.

The upright stanchions that hold the coal rails are from "T" shaped brass extrusions, coal will disguise any shortcomings in representing these fully. The bi-fold door can be seen clearly here, it needs some sort of restraint to hold it closed.

The bi-fold doors are closed, however the engine will not negotiate the curves on an average club layout with them in this position so they'll have to remain open when the engine is in action. 

The fall plate has rather large cut-outs so that the engine can negotiate curves, the bi fold door on this side is held in place by a length of chain. The cab floor is made of wooden slats from a model ship kit. 

Most of the rivets here are brass ones soldered into appropriate locating holes. The hinges of the inspection covers over the slide bars are short lengths of wire held in place with Super Glue.

Crew on the alert watching the road. The figures are available from Invertrain. At the moment the cab roof can still be removed so that the backhead can in turn be removed for painting. 

HR Loch class 4-4-0...the complete engine and tender.

A Crew for a HR Loch.

Crew seen with the roof removed

With the roof in place the cab interior is still a focus of interest and detail.

Little of the backhead detail is obscured by the crew.

Fitting figures into cabs so they don't fall over...How to do it...As construction of my HR Loch approached completion I turned my attention to providing a suitable a crew that would fit the cab without unduly obscuring the backhead detail or appearing to crowd the rather restricted cab area. You can judge for yourselves the degree to which I've succeeded. Both the figures are fixed in place with short lengths of brass rod. The driver on the left of the engine has a short 0.6mm dia. rod fixed in his bottom which locates in a corresponding hole in the splasher top. The fireman has a similar rod inserted into a hole drilled through his foot and up his left leg which locates into a hole in the cab floor. The figures are securely in place and do not fall over when the engine is in motion. I'm sure that this is the best method of fixing figures in place in cabs, they can be removed at will and the tiny locating holes are hardly visible.

Both these figures, which I designed with the cab of a 4-4-0 in mind, are now available from Invertrain

Sunday, 4 December 2016

HR Loch an Dorb progress.

HR Loch class tender original length though without rear toolbox.

The main structural components of the tender are from the Lochgorm kit though the tank corners and curved coping are sections cut from brass tube as I could not bend the material of the kit, the coping was too intransigent and the corners kinked when I tried to bend them due to the oversize holes for the corner handrails. The steps still need improvement to remove the etched outlines above the horizontal part of the step.

HR123 in 1923. Courtesy of the Highland Railway Society.

A rear view of Loch an Dorb at Blair Athol in 1923 in the HR collection at Am Baile shows her running with an original tender with a rear toolbox. However the above picture, which I believe was taken in either 1923 or shortly after, shows her in HR livery with what I interpret as an original length tender though with the rear toolbox removed. A shorter one can be seen mounted behind the driver. The tender has at this time not yet been lengthened to the full length of the footplate. This is the style of tender that I've modelled (above). 

Smokebox and footplate detail

The inspection covers above the slide bars were represented on the footplate by an unsightly etched outline. I cut along the etched lines to create a rectangular hole in the footplate and made an infill to represent the covers which just need some tiny hinges to complete the effect. There may be something available in Archer Surface Detail transfers that will fit the bill.

Cab roof constructed from nickel sheet silver with brass extruded cross ribs. 

The roof is made from sheet nickel silver though the front curve is a section of brass tube, transverse ribs are extruded brass section. The tablet catcher on the cab side is an LGM casting to which I've added a handle that protrudes into the cab.

Detail of cab and backhead with roof removed.

There are three sources of information for the backhead detail; a drawing by Peter Tatlow; a GA of the 1917 engines and of course the backhead of the preserved Jones Big Goods in the Transport Museum in Glasgow. Though I've mainly based the details on Tatlow the other sources have helped too. Castings are mainly LGM, some of which are a little oversize, they have been reduced to the right scale with an unavoidable though slight loss of detail.

The oversize inside splashers contribute to limit the space available for a crew, which in the case of a 4-4-0 with so visible a cab interior, I consider mandatory.

The fall plate is attached to the engine and because of the protruding side wings and stanchions on the tender footplate I've had to make the fall plate cut-outs oversize to accommodate these as there is a good deal of movement between tender and engine on corners. Fall plates and tight corners are not compatible and neither I suspect are cab doors, particularly the bi-fold variety that the Lochs carried, though this is a problem I've not yet examined closely.
I don't think the engine will ever be happy running in reverse, however as the Highland did not encourage this practise it shouldn't present a problem.  

Thursday, 27 October 2016

HR Loch Valve Gear

HR Loch chassis progress so far.

The Loch class employed Allan's Straight Link valve gear and the parts and castings to build this feature are readily available from LGM.

The valve gear is suspended from the links that depend from the reversing shaft levers which are situated above the radius link on the reversing shaft.

The forked ends of the eccentric rods attach to the straight radius link in which the jointed valve rod pivots, these parts were assembled to form two separate units. This part of the valve gear is fairly easy to fathom from available drawings and is intended to work, the eccentrics will motivate the radius link and the attached valve rod will move horizontally.

More obscure is the manner in which the valve gear is supported from the reversing shaft lever above and this is where the model and prototype are going to have to go different ways as I don't think it feasible, at least not without huge effort, to model this feature of the valve gear according to prototype.

The lifting links depending from the reversing shaft levers will not be attached to the valve rod and radius link prototypically, they will remain cosmetic. They don't move anyway, at least not much, other than when the valve gear is reversed.

Allan's straight link valve gear rear view from above.

The complexity of the arrangement of links depending from the reversing shaft levers is evident in this view, the rear lifting link attaches to the forked end of the rear valve rod. The front lifting links attach to the radius link.  All the parts are now in place though the lifting links are not attached to the valve gear, they remain cosmetic.

The reversing shaft levers are mounted on the transverse reversing shaft just behind the motion plate.

Loco body in place showing the gap under the boiler through which the valve gear can be seen.

When your eyes accustom themselves to the murk under the boiler and you get in close there's still not a lot to be seen through the gap between boiler and frames. Most of the movement will be in the gloom behind the motion plate...and Yes, it has occurred to me that inside motion in this case might not be worth the time spent on it.