ALCO RS-11 by Rapido Trains

[Schraddel]

O.k.,

some further modifications:


When the RS11 was halfway in pieces, then let's do some work to eliminate the diagonal stiffness.
The photo shows the direct suspension of the trucks. Both trucks are done equal in this manner. Not bad and standard practice not only by this manufacturer.
On the main frame you see the cast on kingpin. This pivot point is only responsible to guide the main frame in all horizontal directions and take all resulting forces.
But for the vertical component there are these 2 half round nubbies responsibe as seen at the ends if this little cantilvers left and right on the top of the gearbox housing.
So this truck is able to deflect and able of rocking along the horizontal transverse axis, but is not able to stagger along the horizontal longitudinal axis.
For one truck this is o.k. But both trucks built equal in this manner this is resulting in diagonal stiffness. The trucks are not able to compensate distortions of the track. Of course you can say, oh it does'nt matter because my tracks all all super even laid. But i am a person who likes switching and somtime there are some "secret" reasons of stalling on apparent even track. And more worst, on unven track are likewise secret derailments seemingly without any cause. These are big big killjoys.
So, what can you do to get rid of these killjoys?





First, grab some washers, rings and so on.





Second, stack these washers, rings etc. on top of the gearbox of one of the trucks until the summed up height of this collcetion reaches the height of the nubbies.





Third, cut the nubbies off.





Fourth, stack the collection of washers onto the kingpin of the main frame and fix it there by some glueing.





Fifth, cut or file some material from the lower ends of the lugs of the worm housing cover. In some cases this in not necessary, but in some cases it will be. This enables then this truck pivoting freely on all 3 axis.







This loco model has gotten now an all wheel stay permanently onto tracks by the means of an 3-point suspension. And for my experiences, the reliability of uninterupted current pick up has a significant enhancement. And derailings on worst laid track are tending to zero.


This is a modification done after sales by the customer.

There are possibilties to do this during the construction phase. The key therefor is not to alter the trucks, both are still produced as before using the same mould cavity of the same mould.
The trick is to modify the main frame. On one end of the main frame the truck suspension will stay unchanged. The weight of the mains frame will be beared by the nubbies as before which will also act as staggering suppports.

But the suspension for the other truck:
- instead a stack of washers machine the mould, especially the part of the cavition for the kingpin
- a shoulder should be originated by drilling out the bore for the kingpin about half of the depth
- this results in a kingpin with a step
- make space for the nubbies in the main frame
- this enables the nubbies to "dive" into the main frame
- for the mould it will be meaning to fill up material here
- may be too late here for the RS-11, but think of it when you are designing the next mainframe fpr the next project
- the weight of the main frame here will be beared by the modified king pin


Utopia?

Not really, here is a example out of the past:

Roco/Atlas 1970's.

When it could be done 50 years before, so why not today too?

As said: Think of it!
The costs for this kind of 3-point suspension are near Zero. (if done during the construction phase and thought of it)

Do i have knowledge about designing model railroad locomotive?

Definitely yes. I was involved into design and costruction of this truck of an European prototype.


@Wayne
So, now you can send the link. Although i am not finished here.


Lutz