Welcome

Live steam model on 7¼" gauge of the Württembergische T3 no 924

Welcome to this blog. It will inform you about the progress of designing and building miniature live steam, coal fired locomotives for passenger hauling. Currently I'm working on a 7¼" gauge, scale 1:8, German T3 steam locomotive.

In 2006 I started this new project. This is a small 0-6-0 branch line locomotive of the German KWStE (Königlich Württembergischen Staatseisenbahnen) origin with outside cylinders and Walschaerts valve gear. The loco is about 1.10 metre long and will weigh approx. 100 kg.

On the left you'll find the index where you can browse through the different articles and on the right you'll find all the extra's. On the top tabs you'll find a brief description of my other locos.

Enjoy this site. Erik-Jan Stroetinga. The Netherlands. Europe.

Sunday, 11 November 2018

Omk Güterwagen (2) Iron work

Although the main body is made of wood, there is a lot of iron work to be made for this wagon. 

On the real full size wagons these sideboards were removable (in German 'abbordbar'). The sideboards had iron T-profiles ('Kastensäulen') that were inserted in V shaped holders located on the side of the floor. The end board, where the brakeman's cabin is located, was not removable. 
The doors were pressed from steel plate (to give them more rigidity) and had a steel riveted framing. 



Offener Güterwagen (Omk O Halle); my drawing as it is to date (December 2018)



After a primary coat of paint, to protect the wooden structure against stains and dirt during construction, the first metal parts were glued on the top of the sideboards. 

These are aluminium angle profiles (10 x 10 x 1.25 mm), sourced from our local DIY-store. 

They are glued with an universal kit. These profiles, as on the real wagons, protect the top of the wood against damage during loading and unloading. And even a 1:8 scale wagon will have to endure a hard railway life.  

Next thing to make are the T-profiles (Kastensäulen) . These 14 x 11 x 1,5 mm T-profiles are not available, so they were made by silver soldering two steel strips together. They are fixed to the wood by M2 screws and nuts. 

The corner profiles (L shaped 20 x 20 x 2 mm) were available through the model engineering suppliers. They are however cut to correct dimensions on the milling machine. The profile is fixed with standard wood screws, which are covered behind support plates.

In later live these wagons got these extra support plates on the fixed end board. This way extra stability was given to the permanent fixed end board.

Also these outside tension strips were added. (In some earlier versions of these wagons,  they were mounted on the inside of the boards). They were needed to take up tension forces, that occur when the wagon was fully loaded (15 Metric Tons). The main frame could flex, and because of this the side doors could not be opened. 
(On real wagons the frame was constructed strong enough, but as light as possible, so that a maximum of load could be carried, without exceeding the maximum axle load.)

The T-profiles, in the middle of the board, have a space to clear the tension strips. Therefore they have an indention in them. From a piece of brass (will not damage the steel during the pressing process) a punch and die were made. 

In the vice, the strip, is pressed in shape.

Not a very high-tech solution, but it does the trick. 

The result after pressing. However there are two sets of punch/dies needed. One for the front and one for the back part of the side board. 

The T-profiles, with the clearance, during silver soldering. The strips were held in position with a small clamp on the end. 

After silver soldering, steel always gets very oxidised; to remove this black layer of flux and oxidation, the strip is left for about 15 minutes in household cleaning acid.  

The T-profiles were made with an over length. After fitting them to the correct position on the wagon, they were cut to length.  
I thought that they we nicely evenly spaced on the board. But the works drawing revealed that this was not the case. Wagons with a brakeman's cabin have uneven divisions, even in front and back of the wagon.  A book of German open goods wagons even explains this; but I could not find any reason why this was different from the wagons without a brakeman's cabin.

In the meantime, a club member of our society Stoomgroep Zuid, came along with his newly acquired  3½" Rob-Roy. 

On the model the connection for the steam whistle had still to be made, and he asked me if I could help with that. 

The brake shoes for the wagon were 3D printed in stainless steel 316. 

A small angle is riveted to T-profile. This was used on the full scale wagon as ledge for a crowbar.


The small ledge in position. Below this a V-iron will be placed, in which the T-profile is held to the wagon. 

In between another club member came along with his 3½" contractors narrow gauge engine. The piston sealing was in bad condition and we reworked them for taking up Teflon piston rings. One piston was in such a bad state that it had to be replaced altogether.

For the V-irons a punch and die were milled from a piece of brass bar. 

The 1.5 mm steel strip was bend into a V shape first on the folding machine, before it was positioned in the home made punch and die.

In the vice the bending was done in one operation, by screwing the vice down. 

The following photos show the bending process. 




All eight V-irons, ready for the next step.

Again in the folding machine, but now with a special narrow top clamp, making it possible to make a small lip on the V-iron.

Cut to length, all eight are ready for fixing on the wagon. The holes for the M2 bolts were drilled with the CNC-milling machine, to speed up the work and to make them fully interchangeable. (I've noticed that these parts are easily mixed-up during the painting process).  

Here the lip on the V-iron and the ledge on the T-profile are clearly visible. As stated above,  a crowbar could be positioned so that it could lift the T-profile (and hence the side board) from the wagon.
These detachable side boards were standard on these so called "Omk O Halle" open goods wagons 

The side boards almost complete.

The first step in making the hinges. Milled from 6 mm steel strip and drilled and reamed round 3 mm.
Working side by side gives sufficient grip in the milling vice, for these operations.

After the previous operation, they were cut in two with the hand saw. 

With so called filling buttons, the radius was made by hand. 

The set op 8 hinge parts; drilled and tapped with M2, so they can be fixed to the T-profiles. 

In position on the wagon. 

The second part of the hinge (the part that will be riveted on the door) was a bit of a puzzle. It's made of 1.5 mm steel plate. 

A piece of  round 3 mm hardened rod (the end of a broken tap), is used as a punch. 

In a piece of mild steel, a gap with a 3 mm radius is milled. In the vice the piece of rod is pressed in the die.

With a nylon hammer the last piece is bend, to make the full circle. 

The strip in between the punch (rod) and die. On the rod a few turns of tape are wound, so that it will not slide trough the hinge when in the vice. I learned the hard way; it dropped to the floor too many times.

The final lug of the hinge after forming. 

The pieces of 1.5 mm sheet metal, with the lugs formed. 

The lug was than bend in the folding machine to the correct off-set. 

Testing the hinges. They could now be cut to size to fit the doors.

The drawing of the rivet locations for the door. On the works drawing of the full size wagon, there is a different spacing for almost every row. 

The hinge roughly cut to size.

The bottom L-angle profile, drilled and ready for riveting to the door. Loctite 601 is used between the profile and the sheet. It's not for strength, but for preventing the ingress of water in later life.  
The wagon will get wet during a rainy day, or during an overnight stay outside. If water is trapped between the plate and strip, rust could occur between these connections, which is hard to remove. 
I saw photos of real wagons were the plate was completely bulged between the rivets due to rust. I hope the Loctite film and paint will prevent this problem for years to come. 

The door getting its shape. With these profiles and strips attached to the sheet of the door, the overall stiffness and rigidity is even more improved. 

The top hinge fixed on the door. There is not much possibility to adjust the door. It has to be made and fixed directly in the correct position. This was done by first clamping the hinge to the door, test the position (by rotating the door and check the height) and than drill the holes for the rivets.  

The two doors for their test fitting. The width was adjusted by filling them to size. Only a few tenth millimetres had to be removed. 

The inside.

Next step: the closing and locking mechanism have to be made. 

With a length of just over one metre it is rather a big wagon, on 7¼" gauge, in my small workshop. An 0 gauge model is standing inside the wagon.