Hornby Thompson L1

[atticombe]

My Hornby L1 whilst a superb runner has suffered yet again with a fractured bottom chassis plate at the first screw holding the front pony truck allowing the truck to fall onto the track. Has anyone else suffered this problem and is there a way of preventing future fractures?

This is the third time it has occurred each time requiring a new plate

[Theakerr]

Funney,

I just happen to have an L1 apart to fix the marriage (rocky) between it and a concrete floor. By the way Thanks Peters Spares. Anyway, I have just had a good look to see if i can see any reason for your problem. I really cannot. There does appear to be two little round marks that may be the remnants of the moulding process. If they were raised a bit they might create a lever effect. The second thought that comes to mind would be check that the cylinder moulding is all the way down. It strikes me that if this were sitting a bit high it might create a pivot point.

[atticombe]

Funney,

I just happen to have an L1 apart to fix the marriage (rocky) between it and a concrete floor. By the way Thanks Peters Spares. Anyway, I have just had a good look to see if i can see any reason for your problem. I really cannot. There does appear to be two little round marks that may be the remnants of the moulding process. If they were raised a bit they might create a lever effect. The second thought that comes to mind would be check that the cylinder moulding is all the way down. It strikes me that if this were sitting a bit high it might create a pivot point.

Thank you for your reply and taking the troubble to proffer a solution, to me it seems that there is a design fault in that the support/retention of the pony truck is via cantelever which lacks the strength in the plate to hold the truck firmly. I will however persevere.

[34theletterbetweenB&D]

But there is no screw retaining the pony truck on this model.

 

I have fiddled about with both my L1s to eliminate the pointless twin pivot camming arrangement that Hornby inflict on the pony truck. That involves deflecting the keeper plate to release the pony truck, using a rotary side cutter to hack away the two stubs on the upper keeper plate, and drilling a hole in the lower keeper plate and inserting a self tapper as the new pivot for the pony truck. If there was any intrinsic weakness in the lower keeper plate, my feeling is that this process that would have likely found it out. Yet I am at 2 out of 2 (big sample!) trouble free.

 

Possibly some other misassembly or foreign material on your model is preventing the keeper plate(s) seating properly, and stressing them once the screws are tightened?

[Theakerr]

I have just finished re-assembling one bent L1 (and have gained a great deal of respect for those Chinese Ladies who put together the valve gear). During the process I did find another possibility for your problem. Specifically the wheel keeper plate may not be going all the way home onto the the two pins that "drive" the front bogie. These pins are attached to the cylinder (piston) block moulding. Basically I found on my friends loco that there was a small (very) amount of movement on this moulding and in conjunction with the wheel keeper plate "movement" the pins and and their respective hole in the keeper plates did not quite line up leaving the keeper plate with a bend in it.