Narrow gauge tramway loco

[Design-HSB]

With the Xrot R12 I solved the following dimensions:


There are 2 different bogion frames and this is the rear.
However, the front bogie is already ready.
Since the slingshot has a gigantic model weight, the boguas actually have no suspension but end stops. These end stops are adjustable via the counter nuts. From these end stops, the wheels can still spring out of the springs by means of small compression springs.


Here the counter bearing from the bogie with an axial ball bearing like the model.

On the side, as with the model, there are only sliding plates, so that rocking prevents the construction. If your tram has to enter and exit in control tracks, it is recommended to make a bogie around the longitudinal axis tiltable and the other bogie to the other bogie. The axles of the R12 are minimally spring-loaded, but you can also achieve this excellently by a rocker technique of the bogies. For this purpose, the bogie must be divided lengthways and additionally made movable in the middle at the pivot point.

Definitely a very interesting project.

[Bernhard]

Peter, I would suggest to fix the bogie to the locomotive body with a screw. If you tighten it carefully, you can adjust the axial play very small. The pivot and bore should have as little play as possible.
I would not recommend a spring preload. The bogie cannot turn freely with it, which can lead to derailment in curves.

Bernhard

[Peter_T1958]

For this purpose, the bogie must be divided lengthways and additionally made movable in the middle at the pivot point.

Hmm, this could work, even in such a small scale compared to your ,,huge" Xrot! Would that mean, the second (rear) bogie should be non-motorised?!?

Peter, I would suggest to fix the bogie to the locomotive body with a screw. If you tighten it carefully, you can adjust the axial play very small. The pivot and bore should have as little play as possible. I would not recommend a spring preload. The bogie cannot turn freely with it, which can lead to derailment in curves.
Bernhard

Thanks for your hint - I didn't realise that! At some threads in different forums I could make out coils springs around the screw. Here a quick sketch:



This corresponds approximately what you are proposing, yes (?)

[Hauk]

Regarding the attachment of the trucks (bogies) to the body; I used the "three legged stool" principle for my Westinghouse engines.  One bogie (A) is allowed to rotate freely in both planes. This is just like the drawing you postet right after I first posted this message!  The other (B) is allowed only to move in the horizontal plane.





I use that same principle for the wheelsets. One axle is fixed to the bogie (two "legs"), and the other is allowed to swivel sligtly (one "leg"). This works well for my bogies, since only the fixed axle is powered. A more elegant solution for making sure that all the wheels are in contact with the track would be to use sprung axleboxes. Unfortunately, mys skills are not yet up to that task.

When it comes to the wheels, have you compared the prototype wheel profile against your chosen Slater Wheels? I dont know If you you are planning a stand-alone model or have plans for more rolling stock and perhaps a layout. If the latter is the case, you should consider a complete set of standards. This would include wheel profile, back-to-back, exact track gauge, check gauge etc.

[Peter_T1958]

Sorry for the delay in my replay – although the number of cases still is stagnating in Switzerland, the daily work has become demanding too due to the legal guidelines, huh...   

Thanks for your inputs, Bernhard and Havard!
@ Harvard
It may well be that I am slow on the uptake, but I do not really understand what you mean with the first sketch. How exactly should I interpret that bearing points? Sorry!
Anyway, I have to point out, that the space between the upperside of the motor/gear unit is limited due to the motor located very (!) close to the centerin pin...



All the best,
Peter

[Peter_T1958]

Hi

It has been quite some time since I could post an update here. Some further work happened in the meanwhile – not only successful...
First, an attempt to print the +GF+ coupler (widespread in Switzerland) in steel. Almost this would have worked  despite the thin walls... but only almost!
Unfortunatel the thin walls wraped slightly:

 

So back to square one!


Much more successful were the reworked etching parts. Here the superstructure, the cab interior and the frame.

   

I'am afraid of messing these parts up when soldering (here the lack of experience is noticable).
However, a first try with some spare parts in hard soldering with soldering paste looks promising.

Hopefully I will be able to show some successful results soon!

[Ray Dunakin]

If that coupler is made of steel, perhaps you could heat it red hot, then press the thin part back into correct shape?

[finescalerr]

The couplers look beautiful. Too bad they warped. Given your skill and artistry, I am certain you ultimately will solder together the etched parts perfectly. The project looks extremely promising. -- Russ

[Design-HSB]

Peter, wouldn't pressure in silver perhaps be the better solution? It can be if the steel is too hard that you can't straighten it.

Is the etching board from Solingen?

Definitely a nice project.

[Bernhard]

Maybe it would be better to print/cast the couplers in brass. You could certainly straighten them better if they are warped.

Bernhard

[Peter_T1958]

Hi gents

Concerning working with brass I have to go through a long and steep learning curve. After some (or more) unsuccessful attempts with soldering, success is growing slowly but steadily.

First trials in bendig and soldering the etched parts (@ Helmut: Yes, from Solingen):






Then I received the gearboxes from my local caster. Now they have been sent to a precision mechanik to be reworked. But even as raw casts, all bores worked already fine !





And here my present efforts in hard soldering. It is easy to identify the first attempt 

[finescalerr]

Nothing wrong with any of that. I can't see any problems from those photos. -- Russ

[Barney]

i Agree with all + great work
Barney

[Bernhard]

Nice work, Peter!

Bernhard

[Ray Dunakin]

Wow, nice work!