How to build a T3 - Part 7
Step 13: Buffer beams
The only really glaring omission from our model so far is some means of coupling it to carriages and wagons. As far as I know, all T3's were fitted with standard buffers and chain couplings (a few were additionally fitted with centre buffers for hauling narrow-gauge wagons on mixed-gauge track, but that's another story...).
The buffer beams themselves are just boxes. At the front, we need a box from L==66 to 86, H=86 to 112, W=+/- 111. We will also need a couple of panels to represent the front end of the frames. The rear buffer beam is siimilar, running from 773 to 793, but is extended to the full width of the cab. Imediately in front of the buffer beam under the cab are the toolboxes: they can be represented by a single box stretching under the cab. If we feel keen later on we could think about detailing the toolbox doors, but they aren't very conspicuous. The cab steps hang on the bottom of the toolbox - each step is a box, and there are a couple of straps (a single panel for each) supporting them.
While tidying up the back end, we can also make the widened part of the footplate that forms the step round the edge of the cab and bunkers, and move the rear end of the well tank to where it should be.
For most Rail3D modelers, myself included, buffers are something one builds once, then keeps re-using in slightly modified form. For once, instead of saying "here's one I prepared earlier," we will try to build one from scratch...
Since we shall need four of them (and they might come in handy elsewhere), it is a good idea to make the buffer as a component.
Name KPEV_T3_buffer Component Metric #Origin is centre of buffer face ... [end]
We can then make the buffer using the cylinder tool, in much the same way as we did for the chimney. A nice trick is to make the front face with a transparent texture instead of triangles from the cylinder tool. Find a suitable photo, overlay the buffer area with a black mask with a circular hole in it, crop, and resize it as a square 256-colour bitmap. I used 64x64, but smaller would be fine too.
We add the buffers to the model with:
Include -100/0/105 KPEV_T3_buffer Include 100/0/105 KPEV_T3_buffer Include -100/859/105 !KPEV_T3_buffer Include 100/859/105 !KPEV_T3_buffer
For couplings and brake hoses, here's one I prepared earlier...
This is a good moment to look closely at your model in the D3D preview and compare it with photographs. What parts look wrong, which details are most obviously missing? We won't be able to model all the details, but it is important to decide what we need to include to make the model work as a representation of the real T3. Some of the things that strike me as strong candidates for inclusion are:
- Lanterns
- Safety valves
- Tank filler standpipes
- Springs, at least for the leading axles
- Compressor and air reservoirs (not needed if we're modelling the early days, but essential otherwise).
- At least some handrails
- Reversing rod, some boiler pipework
Lanterns are easy - just a cylinder with the panels on one end face given the *HeadLight property, a bracket and a handle. They are made as a component, like the buffers.
The safety valves sit on a small cylindrical mount on the back end of the boiler (L=575, R=15). They are long brass tubes, the spring and lever mechanism (simply a box with a spring texture) fits between them.
The tank-fillers are simply large diameter pipes near the front of the bunkers, whose purpose is to get water from the usual tank filler height of other locos to the well tank. They are easily made with the cylinder tool.
The springs sit under the boiler. The leaf springs and the compensating beam that equalizes the load between the first and second axles are just boxes, manually tapered at th ends. The rods that transmit forces to the wheels and frame are just single black panels - given the location, there isn't much chance of getting your viewpoint anywhere where this really stands out. There's no real need to model the springs for the third coupled axle, which are hidden by the bunkers.
The compressor sits on the right-hand footplate. It consists bascally of two cylinders, connected by some thin rods. The lower cylinder has cooling fins, represented by the same texture as the safety-valve spring. The air reservoirs are just cylinders. Some T3's have a single transverse reservoir, but the one in my drawing has the other arrangement with one hanging under each side of the cab.
To make reasonably thin handrails, the best answer is probably to "cheat" again with a texture shaded to look like a curved surface. This allows the handrail to be made with a single panel. The same approach can be used for pipework. As usual, it is a matter of deciding where to stop: there are lots of pipes, even on this very simple loco!
For the purposes of this exercise, we can stop here.
Download the detailed model
The final stage would be to individualise the model. At the moment, we have a generic model that does not represent any specific member of the T3 class or any very precise period. There were over 1500 T3's built for many different state and private railways, and quite a few closely related types elsewhere. What about "Bello"of the Dutch Stoomtram Hoorn-Medemblik, or the BR89.60 (a T3 with a six-wheeled tender)?
To do this, the trick will be to collect together the parts that are common to more than one model as components, so that each version only repeats the parts that are unique to that version, and calls the rest with Includes.
But probably the next serious job before starting on that will be to make a few typical German Lokalbahn coaches for this engine to pull.