My part built TICH has developed a problem with one of my Walschaert’s gear :-(

[Mike PalingParticipant @mikepaling69128]

Hi …

My half completed large boilered Tich, with Walschaert's gear, seems to have developed a problem recently.

Some time ago I tested the completed chassis with compressed air and it ran really smoothly and showed no problems …. so I have been slowly carrying in with the rest of the loco since then.

Recently I have noticed that when i push the loco chassis along it seems to there is something binding on the crank of one of the back wheels and it tries to lock up. I can see the wheel lifting up slightly as I push the chassis forwards. I have spent hours trying to figure out what is causing this problem and I cannot make any sense of it …. I hesitate to take things apart as I don't really know what I am looking for.

As far as I know the wheel has not rotated on it's axle and all linkages look as if they are all in their correct positions.

Could I have knocked something by accident at some point and caused the crank pin to bend slightly? …. or is there something else that might be causing the problem?

Any help and suggestions would be very much appreciated.

Mike

[Mike PalingParticipant @mikepaling69128]

[CirclipParticipant @circlip]

When you air tested it, the wheels were unloaded? ie. the chassis was suspended? Try air test again if successful there must be binding caused by the weight of the chassis on the linkages.

Regards Ian.

[Mike PalingParticipant @mikepaling69128]

Hi Ian ….

It was air tested with wheels rotating sitting on a special jig ( loaded ? ) that belonged to a friend.

This happened a few years ago when I was in New Zealand …. I have since moved back to the UK and no longer have access to this jig.

As I said in my initial message all seemed to work really smoothly …. not now for some reason.

The problem is more pronounced when the Reversing Lever is in the "central position" …. and noticeably easier when it is moved to either extremes. Is this a clue to what the problem might be?

Mike

[Author]

Posts