Some of you may not know that Southwark Bridge Models grew out of a 4mm private layout based upon the abortive Southwark Bridge station planned by the LSWR as the ultimate city terminus beyond Waterloo. It has been built by a band of enthusiasts who make no concession at all to compromise and include among its number such luminaries as Henry Bousher. Absolute fidelity to prototype is the order of the day for this group. Since there were few, if any, suitable kits for some of their stock needs, Ivan Smith produced kits for the group. He made some of them available for 7mm (and not by just blowing them up other manufacturer’s please note). This odd vehicle is a result and was built for and in conjunction with Ian Hopkins.
What's in the box? The kit arrived as an etched sheet about 550 x 300mm bound in a couple of sheets of hardboard, together with comprehensive instructions, drawings, historical background, list of parts, a couple of bags of bits and castings and map of the etches. Do make sure you have the latest issue of the instructions. Ivan will provide them for you on request. Study of the provided information is highly recommended since this is decidedly not a kit for the beginner.
The springs
One does not necessarily need to start where Ivan suggests so, just for the hell of it, I started with the springs, which are a very neat set of etched laminates producing elegant and strong replicas of the real thing. These were provided instead of white-metal castings on the basis that they would be more accurate, much thinner and far tronger. I completely concur with this having built a couple of other kits similarly designed. The springs
I soldered each set of four laminates together clamping them with cut down aluminium hair grips and lining them up with some 0.5mm wire in the centre and outer etched holes, making sure that all the wires were parallel before soldering. However, if I were doing another set I would drill suitable holes in the RSU plate and assemble the prings on pins inserted into the RSU plate.
Ivan suggests a slightly different method, equally valid. I later discovered an extra, undocumented, layer of spring etches at the edge of the sheet, Ivan thought that the springs were a little too narrow and provided an extra layer to go behind the four you see above. I went back and added them and they are much improved.
The floor and solebar assembly.
The next job was to sweat the solebar bases to their overlays and build up the headstocks. Both the solebars and headstocks stood proud of the floor of this vehicle so that one can see a distinct gap.
Floor and solebars being assembled
Headstock assembly.
Some care is called for in assembling the parts. Normal seaming is not an option here and so I soldered both the tabs in the slots (4 each side and very accurate) and the spacing tabs. The floor itself also curves in at the ends.
It is essential for this kit to file of the cusps for most joints. On occasion too it is necessary to open out the slots a little with a scalpel blade. The photo clearly shows how visible is the gap. Some care is needed to ensure that strong soldered joints result, combined with a square and flat floor upon which to build the body.
The headstock, already two laminates thick, requires two further thicknesses of brass ogee moulding to give the proper depth. These are fiddly but well worth the effort once they have been carefully filed to match the complex curves used in these early vehicles.
Soldering the headstock in place requires a high level of cleanliness since there is not a lot of surface area to join together. One is left with the distinct impression that the Southwark Bridge Group do not take prisoners.
The floor with solebars, headstocks, buffers, coupling hooks, centre wheel set guides and pivot bolts fitted
The coupling hooks are made from three layers of laminate that, once filed to shape, make up into excellent representations of the LSWR's version of the gedge hook. There are etched holes in the extension under the floor to take the buffer springs, most of which got cut off when fitting the Cleminson trucks to prevent fouling.
The Cleminson suspension.
The photo shows the part completed set of three units for the Cleminson 6-wheeled suspension. One set has the springs fitted prior to them being modified with the extra layer. Provided one follows the excellent instructions, these units are not difficult to produce. The slide rods call for 1.4mm brass rod. There was none
provided in my kit (an oversight that I am sure Ivan would have rectified rapidly had I taken the trouble to call him) so I used some 1.5mm rod I had on hand and opened out the holes and slots accordingly, very carefully.
The Cleminson suspension parts.
The wheels. Like many 7mm kits, the wheels, if installed as suggested, will be trapped in permanently due to the very long bearings provided with Slater's wheel sets. I wanted to be able to spring the wheel sets out to make painting easier. Here is how I did it. The parts needed, wheel set, top hat bearings and two washers 0.2mm thick from the kit etch. First, cut the ends off the axles, file the end square and de-burr so that they extend only 2mm each side. Insert the top hat bearings into the holes in the W-iron and then insert the wheel set with a washer between the wheel and the bearing as shown in the photos.
Centre the wheel set and, holding the bearings tight against the wheel, solder one bearing in place. Turn the unit round and solder the other bearing keeping both bearings tight against the wheels. Spring the wheel set out and remove the washers. When they are put back there will be about 0.5 to 0.75mm side play.
The wheel assemblies.
Brakes
There are two options for brakes, either skew or straight. The photos shows the parts for the straight version, which is what Ian wanted fitting. Each brake shoe unit has a shoe etch soldered to either side and all the cusps have been cleaned up so that edges show as a flat surface. The outer Cleminson units have the thicker springs fitted and the bearings have been fitted prior to putting brakes in. The components are quite straightforward to construct but some care will be needed to ensure that the wheels do not foul the brakes.
The brake gear.
The axle boxes (photo) need some modification to ensure they fit correctly. File off the back until one has a flat face and then drill out 1.6mm. Though there is a goodly thickness of material, it is still possible to drill right through. Yes, I did, but got round it by gluing a small portion of a spare Slater's bearing in the hole. The top will need some cleaning up too and it will probably be necessary to file the top lip back a little to get a tight fit against the spring. The axle boxes where then fixed with Loctite 480.
The almost complete set of Cleminson trucks. It needed a vacuum cylinder (not provided in the kit) and another set of Maunsell wheels to complete it.
The body
In the photographs are the parts that go to make up one side. It has both a turn-under (fairly shallow) and turned in ends, so ensuring that the compound curves meet correctly means taking some care. Forming these curves looks daunting but I found it no more difficult than forming a turn under on the sides and ends of early Great Western stock. Take time, use gentle pressure and keep checking for fit. The instructions have a small diagram illustrating the use of an engineer's square when soldering the rails to the sides. When combined with a steel RSU plate and magnets, the job becomes relatively easy.
Turning the side upside-down and clamping it and the rail to the steel plate did this. Then, using the engineers square and lining up the witness marks, the centre was tack soldered.\\TClamped to the RSU plate with magnets
to solder the sides.\\Here is the side with both rails firmly soldered in place with both the turn under and end curve in place.\\The sides and ends as complete as possible waiting to be fitted together. As usual I fitted as much as possible in the flat. The only parts not fitted at this stage are the door handles.
Most of the construction is edge soldering, no tabs, so cleaning up the cusps is essential. Once the main sidepiece had had the turn-under formed the inner top rail was soldered in place. Before continuing, it was taken down and checked carefully that all was square. The curved end was simply clamped with the magnets as shown and the joint seamed up.
The top rail has to be at right angles to the side, but the bottom rail needs a rather more complex solution. It needs to be parallel to the top rail but is soldered 0.45mm from the bottom edge of the side. The instructions suggest some card to support the rail and three layers of a label from one of Big Jim's kits turned out to be just right.
So, with the rail clamped to the card and the plate, the side was offered up. I used a piece of scrap etch pushed up tight against the side, clamped to the plate. The engineer's square was used, levelled with another piece of scrap, to ensure the straight portion of the side was at right angles to the plate. It was necessary to tweak them a little after soldering but using the partitions and ends make it easy to ensure the curves are correct.
The overlays can now be soldered in place. The inner overlay goes first, the instructions are clear about using two holes, drilled out 0.7mm, to align the parts correctly. I then drilled out the remaining holes 0.5mm. The outer overlays were then offered up using four pieces of 0.5mm wire to ensure they were correctly aligned. However, when it came time to fit the overlays on the window end I fitted the outside one first. This meant that I could file the cusps off the inside of the window frames, which makes them much neater, and then fit the inner overlay.
The window end has several layers and so is a relatively easy fit to the sides there being some thickness of brass to work with. The non-window end though is a single thickness of etch. As you can see, I added some strengthening angle strip in the corners, which will be invisible through the opaque lavatory windows at this end.
The window end of one side.
The ventilator bonnets need to be beefed up and there are extra, undocumented, etched backing pieces at the edge of the sheet. Solder the bonnets to these before starting to shape them. The long one over the lavatory window will need a slight bend in it to cope with the bend in the side. There are no guide marks but there are two ways to get them levelled correctly. I very lightly scribed a line 2mm from the top of the etched moulding and used that as a datum for the tops of the bonnets. The other (Ivan's) way is to line up the bases on a line 3.5mm from the bottom of etched moulding. Either way, the bonnets will be in the right position.
I started by fitting the internal partitions after having fitted the door handles. Since the vehicle is to have lost wax outer door handles I used the etched ones doubled up, carefully filed to shape. One point to watch for is that all three internal partitions are exactly alike so once one has sweated two of them back-to-back, the position for the door knobs will be diagonally opposed. Drill the hole in one side in the square indentation for the knob but fill the square on the other side with solder and file flat. I put that side to face away from the end windows on the basis that it will be less noticeable.
Internal partitions.
Next I soldered the ends to opposite sides as here. The intention next was simply to clamp the parts together on the plate and tack solder.
Unfortunately, the body was now out of true. The cause was the partition at the lavatory end. It is the same size as that at the other end, but is placed much closer to the lavatory end. Naturally, it should be narrower to account for the curving sides. It was removed for attention and refitted after the body was assembled.
The roof fixing beams neatly fold up and then fit into half etched fixing points. Another piece has to be fitted nside the fold-up to strengthen the beam. The instructions suggest fitting this before fitting the beam to the roof rails. I thought this would be quite difficult and so fitted the beams and then the strengthening piece from the inside afterward. Be sure to get them the right way round so that the half-etched holes face into the vehicle. The roof fixing beams in the nearly complete body.
The roof will be held in place with half a dozen self-tapping screws.
There is also very little clearance under the body for the Cleminson trucks so I would advise filing the cut-outs for the axle boxes a good deal deeper before fixing. Needless to say I did not and had the delicate job of filing them in-situ.
Ian Hopkins constructed the roof in Plastikard, fitted a suitable interior and painted it in LSWR livery.
This section is written by Ian.
I used Spray mount adhesive spray glue to attach the roof profiles to a piece of 0.040in Plastikard, from the same sheet used for one of the roof layers. Each profile was labelled with its use to avoid confusion during construction. I cut out the profile pieces and set them aside.
The roof layers glued together and one of the profiles.
I next cut the sections of Plastikard for the roof as per the instructions. I found it difficult to cut sizes such as 55.51mm or 44.35mm and simply cut them to the nearest half millimetre over the size indicated. Once cut out, the pieces were laid in a line or order of use and number or letter used them to make later identification easier.
Starting with the base, I marked a centre line on each piece and carefully spread superglue as instructed. Beware, the fumes given off on a piece of O gauge roof can be quite eye-watering. Being superglue you only get one chance when sticking it down, so take extra care when positioning it. If the glue is spread too thinly, it dries out before it can stick the parts together. I found that the edges needed to be sealed with plastic solvent. The layers were weighted and left overnight to set.
Fitting the roof
You need a very coarse file or a rasp to attack the roof when shaping it to match the profiles. You will be appalled at how much mess it makes, but take time constantly to check with the profile shapes. I spread car-body filler or knifing putty to smooth out the curve. I found I had a nice series of steps down the sides due to my imperfect measurement. When dry, in about an hour, I used a coarse file to finish of the profile to correct shape.
The roof was placed on the coach body. I then drew round the body sides to get the taper of the ends. The whole process is rather like shaping a boat hull.
I carefully filed it to shape, keeping the file at 45 degrees and trying to keep the edge of the plastic running in a straight line along centre of the roof to the corners. If the line along the ridge of the roof end appears to be curved left or right, the roof needs more work to get the shape correct.
The next job was the final fitting and making the roof cornices. The roof fittings are shown in the diagram.
The windows are etched with a pattern and behind them are
curtains.
The roof fittings
There is also a fully fitted interior. It is just possible
to make some of it out through the windows.