Rogue bogies on coaches

Old Crow · October 20, 2017, 02:08:03 AM

Having to buy used at present, I've collected a few Farish Mk1 coaches - older Poole, early Chinese and one current spec. I'm having problems with some of the older coaches and one particular that is a nightmare. Hoping you guys have some experience of what can and can't be done with these.

Problem is the tendency for the coach to raise a wheel on curves - always the trailing wheels on the front bogie, leading to derailment. I think the problem stems from far too much horizontal play on the bogie pivot that seems very loose, apart from throwing the passengers around, any wobble can lift a wheel right off track.

Now I see the bogies are attached just by a small plastic pin and, it seems to me, this is too long so the bogie doesn't rest on the chassis bearing but on the pin only, giving great scope for wobbling. Have any of you come across this? The bogies seem so loose they can rotate 360 dgrees! I'd be tempted to shorten the pin a little so that the bogie actually rides on the coach - I see the current spec coach has limited bogie travel and is much better. I'd appreciate any thoughts.

Also note the wheel sets run in very tiny depressions. Are the wheel sets currently available as spares an improvement?

railsquid · October 20, 2017, 04:03:58 AM

Quote from: Old Crow on October 20, 2017, 02:08:03 AM
Also note the wheel sets run in very tiny depressions. Are the wheel sets currently available as spares an improvement?

Definitely, they're not as clunky and are chemically blackend, and are a nice visual improvement. You may need to open out the axle holes very slightly with a small bit if they don't run freely. Whether they'll solve the problem is another question, but all the coaches I've used the replacement wheels on run just fine.

Recent example - old on the left, new on the right:

Bealman · October 20, 2017, 04:48:26 AM

The bogie rotates 360° on many old Farish coaches.

carderrail · October 20, 2017, 06:48:04 AM

One problem that can happen with the old "Farish" silver wheelsets is that the axles does not throught the centre of the wheels so they wobble slightly off centre, I have found this can throw coaches and bogie wagons off the track at random locations.

Easy to check - turn the coach over and spin the wheels - there should be no wobble, the replacement blackened wheels are not always 100% either.

Regards

Tony

PLD · October 20, 2017, 08:54:45 AM

Quote from: Old Crow on October 20, 2017, 02:08:03 AM
Problem is the tendency for the coach to raise a wheel on curves - always the trailing wheels on the front bogie, leading to derailment.

If it is always the same axle that is the problem, look at that axle first... Common things to look for:
Is it the same type and size wheels as the other three on that coach? (not uncommon to find second hand coaches with mismatched wheetsets).
Is it the right gauge? - check the 'back-to-back' measurement (the distance between the rear faces of the wheels should be approx 7.2mm)
Is the axle correctly fitted in the bearings and able to rotate freely?
Are the wheels clean?

Newportnobby · October 20, 2017, 09:55:00 AM

379-412 is the reference for replacement Farish coach wheels but, as has been said, check the relevant axle is sitting properly in it's bogie. It takes very little for them to pop out of the seating and thus not run true.

Old Crow · October 20, 2017, 03:43:37 PM

Cheers guys! I think it's due excessive wobbling of the coach rather than the bogie. As I said, the whole end is supported on the pin and doesn't make contact with the coach body as a bearing. An awful lot of play here; should not the bogie ride on the circular raised "bearing" on the body?

martyn · October 20, 2017, 04:13:04 PM

Yes, it should ride on the circular bearing pad, not the short 'stub' where the push fit securing pin pushes into.

Martyn

scruff · October 20, 2017, 07:49:28 PM

Always make sure the bogie pin is pushed fully home.. as an afterthought, are both the pins the same length? or has one been swapped?
I know the pins on the newer "Blue riband" type coaches are not interchangeable between the mk2 and mk1 coaches because they are of a different diameter. The mk2 have much narrower shafts on the pins.

Cheers
Mark

Old Crow · October 20, 2017, 09:23:09 PM

Thank you. Pushed the pin in as well as I could but it won't go in fully. I took the bogie off and, in my view the pin is just too long. I think about 1.5mm should do it and bring the bogie to rest on the coach chassis.

scruff · October 20, 2017, 11:17:55 PM

The retaining pin should be an interference fit and hold the bogie against the coach chassis.. If the bogie can fall off then the pin is too loose.. If it drops away from the coach chassis but does not fall off then the pin is too long.. To fix this trim a little at a time off the end of the pin and then refit and check for "snugness!" until the bogie sits up against the chassis..

Seems someone has swapped the pin from another coach to the errant one.. hope this helps..

Cheers
Mark

Old Crow · October 22, 2017, 01:40:32 AM

Yes! That's what I'll do - it really is a wobbly coach, far too much play.. Could do with some of the dampers you see on the sides of modern bogies.

PLD · October 22, 2017, 09:00:53 AM

A thought based on some second hand coaches I've just seen...
Are we sure this coach actually has the right sort of bogie attached?? A photo might be useful to check & confirm...