I see TTA tank wagons when I visit Ipswich station and look down on the refuelling point from the footbridge. The wagons always look like a tank with an underframe welded on underneath rather than a chassis with a tank sitting on top. I have wedded a Lima tank to a Lilliput chassis to try to recreate this appearance in model form. The overall dimensions are close to those of a scale model (within a millimetre) but some of the details on the solebars are wrong or missing altogether.
The tank for the model is from the 1970s Lima wagon:
The tank is almost exactly the correct size for a 1:87 scale model of a TTA - the moulding is about 1 mm too long, but most of the error is lost in the incorrect shape of the ends, so the cylindrical parts of the sides look correct. The diameter is 1 mm too big too, but I have masked this with the Lilliput chassis.
The chassis of the Lima model has the correct wheelbase and the two ends can be shortened to match that of a TTA, but is far too wide (it is based on Continental practice) and I cannot see a way to make it narrower. So I have taken the chassis from a Lilliput model:
The Liliput chassis is too short for a TTA and has incorrect details on the solebars, but the wheelbase is correct for a TTA and the moulding is only about 1 mm too wide. This millimetre matches up with the extra millimetre of the diameter of the Lima tank.
The brake end of the Liliput chassis has the correct overhang for a TTA, so at this end I simply removed the railings and cut off the buffers. The other end is too short so I cut off the whole buffer beam and lengthened the chassis and made a new buffer beam with some styrene. Then I added some Markits 4mm coach buffers all round - the buffer heads are probably over-scale for a TTA but I think they look better than the obviously under-scale Continental buffers from Lima and Lilliput.
The moulded data plates on the sides of the Lima tank have to go but I managed to pare these away and preserve the rivet detail underneath them. Then I cut out the bottom of the tank (I took out a strip about 12 mm wide) and trimmed down the two longitudinal flanges to let the whole moulding sit lower on the chassis, and so a mock-up of the wagon now looked like this:
I took the Lima ballast weight out of the tank and put in some sheet lead instead, and the finished model weighs 58 grams. I removed the Lima paint with meths.
The plastic of the Lilliput chassis resisted my usual solvents for styrene and the chassis extension kept falling off, so I added a piece of 0.25 mm styrene across the top of the whole chassis to hold everything together. This sheet being fixed down with cyanoacrylate. It was then easy to attach the tank. Then I added a walkway from styrene, ladders from an etch by Scale Link, and two tank fillers from a moulding of pipes and fittings by Knightwing:
The Kadee couplers have M2 bolts inserted vertically with their heads countersunk into the chassis before adding the piece of 0.25mm styrene. I am hopeful the couplers will withstand operations and not fall off.
I could not face mixing up a two-part primer for the ladder so I coated it with cyanoacrylate and let this dry. This works for me. Then I sprayed the whole model with Railmatch universal primer:
The primer shows up some faults and I filled these with Revell 'Plasto' before further painting. Painting is a still a lottery for me and this wagon didn't turn out as well as I had hoped for. This photo shows the worst of the finish and the model looks rather better in a more diffused light or indeed with some flash from the camera or from a normal viewing distance. The green is Revell Aquacolour '48 sea green', toned down with some yellow and white. The yellow on the solebars should continue around the ends onto the buffer beams but this was too difficult for me to do with the buffers in place. In future I can try fixing the buffers on after painting.
The overall effect on the layout is pleasing, and I can now run a wagon load of aviation fuel to Fairport. Here it will be unloaded into a road tanker to take it on to the airport.
The model runs extremely well with its original wheels, and I haven't felt a need to try adding wheel bearings here. The Lilliput chassis is tricky to work with because its plastic is very difficult to glue. If I try another TTA, I might persevere with modifying the original Lima chassis, this takes solvents much better.
Chassis: from Liliput 250 02
Wheels: Liliput originals
Buffers: Markits MRBUFCR/B coach round buffer