murphy coaches derailing

[derek]

I have just biught 3 Murphy Models mk2 composite coaches and 1 mk2 1st to be pulled by IRM,s Aclass loco. After two or three trips around the layout the coaches derail, despite running at snaails pace. Is anybody else having problems with these coaches?. (I am running them on large radius track) The sprung couplers seem over complicated. Wonder if they are causing problems? 

[Robert Shrives]

Hi Mine are fine, things to check - are all wheels fitting properly and free spinning , do bogies rotate freely - Tip vehicle on its side whilst held in air and bogies should flop down easily - check both ways.  Equally do they tip back and forth to allow for changes in gradient.  

The sprung couplers are normally fine but do check when flicked they return to the straight position - possible to dislodge cam so out of line and then they will jam and a derailment inevitable.  Check location do they sit level compared to vehicle bottom edge and couplings are correctly located.

After that questions depend on how other stock operates on the layout and if derailing always at same location?

robert  

  

[Rush and Lusk]

Hi Derek,

I bought a number of the very same MM coaches from Marks Models over recent months. Upon test running on a provisional, (2nd radius), development layout, some were fine, but a couple were derailing and catching on points. The culprit was the sprung couplers failing to return to the straight position. The guys from Marks kindly replaced the defective units, although I got the impression that this may not be an uncommon issue. 

George 

[Georgeconna]

No sprung buffers on those coaches despite the price tag., the spring set up is  bit too bouncy on the kenitic couplings!

Wonder could you get Baccy Springs and replace then.

[JasonB]

On 6/1/2022 at 7:37 PM, Rush and Lusk said:

The culprit was the sprung couplers failing to return to the straight position.

Exactly, this is certainly an issue, and most likely the cause of Derek's derailing problems. 

I have found, if the coupler is pulled so far in either direction there's a good chance it will lock, and not return to it's original position. 

The most annoying part is, it can happen sporadically and to any coach in a rake, it's not always the same one. 

[Mayner]

Will then MM coaches derail (on 2nd or 3rd radius curves) if the couplers are fixed in the normal or straight position? 

Self-centering couplings used on the MM coaches seems to be a UK/European thing.

Most American coaches and freight cars (HO and large scale) are fitted with body mounted knuckle couplers and will stay coupled without de-railing on relatively small radius curves.

I used body mounted Kadee's on Lima Mk3s, Hornby Stanier, Park Royal and Laminate coaches though minimum radius was fairly large.

 

[DSERetc]

derek,

What era are you running in?  Is it the mid 1970s?   Are you running north over the border? Perhaps you are running too fast through the  Goraghwood de-railing loop. I think that there was a 10mph restriction on it.           

 

DSERetc

 

 

 

 

 

 

 

 

                                         

 

 

[Past-Avenue]

Hi he's MM MK2s that i put Hornby couplings on to get them to run flawless for a friend of mine a while back .

 

  

[Sean]

On 9/1/2022 at 6:07 PM, Past-Avenue said:

Hi he's MM MK2s that i put Hornby couplings on to get them to run flawless for a friend of mine a while back .

 

  

have you documented the mod anywhere i would love to see it.

[Past-Avenue]

Hi Sean 

No i haven't but all that i done (after alot of trial and error with other types of couplings) was removed the tension lock coupling and replaced with the Hornby R8220 . I have fitted these to a few rakes of wagons and seem to work well on my not so level track. I've fitted them to MIR Boggie cement wagons and MIR Fertiliser wagons and MM carven coaches. Hope this helps. 

 

Enda 

 

 

Edited January 27, 2022 by Past-Avenue