N Gauge Forum

General Category => N Gauge Discussion => Topic started by: woodbury22uk on December 12, 2013, 09:37:46 PM

Title: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: woodbury22uk on December 12, 2013, 09:37:46 PM
I have had a TPO coach for a few months which has only ever run at the rear of the train. Due to operator error it derailed today and when I reconnected it to the train I realised that the close coupling arm at one end was not centring. I diagnosed that the return spring must have been dislodged so I removed the body to correct this.Two screws under the chassis release the body. I made sure the toilet water tank filler pipes were not attached to the chassis - they are not.

(http://www.ngaugeforum.co.uk/SMFN/gallery/52/thumb_9036.jpg) (http://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view;id=9036)

The close coupling mechanism is held in place by a metal plate which has two plastic locating pins and is held by a very small crosshead screw. The plate is handed so record its orientation before removing it.

(http://www.ngaugeforum.co.uk/SMFN/gallery/52/thumb_9037.jpg) (http://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view;id=9037)

After lifting the plate and storing the screw on a magnet I realised that the centring/return spring was missing altogether and probably always had been. This return spring is a whisker of springy wire and, of course , it is not the kind of thing I have handy. My solution was to use a length of that very thin plastic thread which forms part of pricing/label tags on clothes.

(http://www.ngaugeforum.co.uk/SMFN/gallery/52/thumb_9038.jpg) (http://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view;id=9038)


(http://www.ngaugeforum.co.uk/SMFN/gallery/52/thumb_9039.jpg) (http://www.ngaugeforum.co.uk/SMFN/index.php?action=gallery;sa=view;id=9039)


I cut a suitable length and lodged it in place and then relocated the close coupling arm, replaced the metal plate, checked the coupler arm centred correctly, and tightened up the screw. This is all much easier written than done, and the amount of swearing involved did attract attention from SWMBO.

The only innovation here was to use the plastic tag thread as a whisker spring. Luckily I had kept a suitable tag after doing a similar replacement on an LSModels SNCF USI coach which is notorious for suffering from dislodged whisker springs.

Sorry there is not an explanatory photo at the moment. Maybe I will pluck up the courage to take it to pieces again to show the innards but not until SWMBO has emptied the swearbox.
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: Newportnobby on December 13, 2013, 09:11:57 PM
Thanks for the detailed info, Mike :thumbsup:
Just think of the wonderful pressie for SWMBO when you empty the swearbox ;)
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: woodbury22uk on December 13, 2013, 09:44:28 PM
Quote from: newportnobby on December 13, 2013, 09:11:57 PM
Thanks for the detailed info, Mike :thumbsup:
Just think of the wonderful pressie for SWMBO when you empty the swearbox ;)

Mick you are too psychic. Just returned from 5 hours penance in the Merry Hill Shopping Centre - I have now done my time.
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: Newportnobby on December 13, 2013, 10:18:42 PM
Quote from: woodbury22uk on December 13, 2013, 09:44:28 PM
Quote from: newportnobby on December 13, 2013, 09:11:57 PM
Thanks for the detailed info, Mike :thumbsup:
Just think of the wonderful pressie for SWMBO when you empty the swearbox ;)

Mick you are too psychic. Just returned from 5 hours penance in the Merry Hill Shopping Centre - I have now done my time.

Having been to the Merry Hell Centre before - you are a saint, good sir
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: Malc on December 13, 2013, 10:28:05 PM
I think 5 hours in Merry Hell is above and beyond the call of duty. I'm champing at the bit to get out after about 20 mins, especially this time of year.
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: woodbury22uk on December 14, 2013, 01:39:48 PM
Thank you for your sympathy. My prize is that I have a load more plastic tags in case I have to do any more close coupler repairs! SWMBO kindly collected them as she transferred all her new clothes to the wardrobe.
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: Newportnobby on December 14, 2013, 05:32:43 PM
Next on the list from SWMBO - a new and bigger wardrobe :laugh:
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: woodbury22uk on December 26, 2013, 04:11:11 PM
Fortified by a good dose of Christmas spirit, I have opened up my coach to take some photos of what was done. For convenience I have added these photos to the original post. Hopefully they will answer any questions which my description did not make clear.

By the way, it was easier the second time, so the practice was not wasted.
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: Luke Piewalker on December 31, 2013, 06:19:38 PM
Bow, worship....

I found the hardest part was getting the body off without breaking anything!
When I opened mine, two very thin pieces of wire dropped out. Fortunately I had a cloth layed out so they didn't escape. Even so if they hadn't have been together I may not have seen them at all...

Anyhoo, thank you for the guide, which gave me the courage to give it a bash!  :claphappy:
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: woodbury22uk on December 31, 2013, 06:53:36 PM
Yes seeing the whisker springs is a major challenge. I would not suggest anyone attempting this just to have a look! Hope the coach works alright now. Mine is better than the original by far.
Title: Re: Farish Close Coupling Mechanism - replacing a centring/return spring
Post by: Luke Piewalker on December 31, 2013, 07:08:15 PM
Annoyingly I managed to initially knacker mine when I took the couplings off to fit the little coupling hooks, then as I was reattaching the couplings must have overstretched something and twoinked the whiskers out...