RPSI MM Cravens (Set of 3) - Available Oct 14th

[pat141]

Pity the wheel are causing problems.

my Cravens are 10.5mm so you would need this size if replacing the wheels.

Try the wheels on another coach to see if it wobbles.

[NIRCLASS80]

Yes the front one was very wobbly but that was just an off centre axle.  They are physically 100% identical to MM Cravens (same tooling).  The only difference is the livery colours, so they should run the same as MM cravens.  I hadn't properly matched the two 071s CV settings for working in consists which seemed to cause some jerky loco action

 

Physically the bogies are 100% different from recent pictures available online.

[NoelG]

Physically the bogies are 100% different from recent pictures available online.

Yes hadn't noticed the bogie differences until saw the IRM post this evening. Had been planning to swap MM Craven bogies with the RPSI Cravens over the weekend to see if it made any difference to the running quality. It's a shame as these coaches look fab but run like dogs.

[Georgeconna]

I have a set put away for me at the Dublin show, Hope they are not all Wibbly Wobbly.Time will tell.

[kirley]

I have a set put away for me at the Dublin show, Hope they are not all Wibbly Wobbly.Time will tell.

 

I'm picking up a set as well, if they all have faulty running then you the man to tell us how to fix it.

[NoelG]

Overall the RPSI Cravens are lovely coaches despite the poor running due to different bogies.  I don't understand why the plug in gangway borders frames are red.  Fine for the optional end plates, but not the frames.  Presume that was a factory mix up.  Also slightly disappointed there was no certificate nor information sheet included about the coaches in the collectors box which was of a low quality construction compared to MM or Bachmann.

[David Jackson]

I have read, with interest, the comments made about the new RPSI Cravens coaches, and have to agree that the livery is very attractive. Unfortunately, I have no interest in such up to date vehicles.

I have also read about the running qualities of these coaches compared with the MM versions, which seems to be due to different bogies being fitted. This is a problem which has afflicted other manufacturer’s coaches over the years, and one which I have successfully cured with the minimum of work. I therefore set about trying to do the same with Cravens coaches. As I said already, I don’t have any of the RPSI Cravens, and my modification has been done on a MM Cravens, but the principle is exactly the same.

I have made a number of assumptions about the RPSI coaches. Firstly that the wheels are running true, secondly that the underside of the RPSI version is the same as the MM version, and thirdly, that the top of the bogie is completely flat, at least at the outer edges, like the MM ones.

 

The method;

 

1. Remove the bogie and coupling mechanism, taking care not to lose the spring.
   
2. Two 4.3mm lengths of 1mm X 2.5mm plastic strip were cut, and glued to the inside of the solebar in line with the bogie pivot. 1mm plastic strip was used as anything thicker would foul the close coupling mechanism.
   
3. Once set, a straight edge was used to ensure that the ends of the plastic strips and the bottom of the bogie pivot were exactly in line.
   
4. If the plastic strips are too long, the ends can be carefully filed until the strips and pivot are aligned. If they are not perfectly in line, the bogie may be stiff to swivel.
   
5. The bogie and coupling mechanism were refitted, and the bogie checked for free movement.
   

 

Only one bogie is required to be done, as this will effectively provide a three point suspension system for the coach. Doing both bogies would make the coach too rigid for less than perfect track.

If the results are less than satisfactory, then the plastic strips can be removed and you can have your wobble back.

 

 

 

       

[kirley]

Thanks David for your 'cure'.

 

I take it your plasticard strips act as cushions to reduce the sideways movement of the bogie.

 

 

If I have the same problem it is something I'll try out.

[David Jackson]

Keiran, the bottom of the strips rest on the top of the bogie and act as stabilisers to prevent the body from rocking side to side. 

[NoelG]

After reading Dhu Varrens excellent suggestion, I spent a bit of time today trying to find out what is different between the Murphy Model Cravens and the RPSI Cravens that may be causing the wobbly running problem on the new RPSI variants.  

 

The RPSI Craven's seem 100% physically identical to the later 2nd generation of Murphy Model Cravens (ie. CIE B&T livery single white strip) including the bogies.  The earlier 1st generation MM Cravens (IR/IE 'tippex' dual white stripe livery) had different bogies and the incorrect length NEM pockets.  I have test run all my MM Cravens 1st and 2nd gen and none of them wobble, but all three coaches of my RPSI set do wobble.

 

Findings

• RPSI Cravens + MM 2nd Gen Cravens have the same bogies, so bogie in itself not the cause.
• RPSI + Murphy Model 1st + 2nd gen Cravens weigh exactly the same so weight not the cause.
• Wheel sets appear to be identical on all three variants
• RPSI Cravens seem to have more play in the bogie pivot mounts - this could be the cause.

The only difference I can find between the 2nd gen MM and RPSI is the bogie pivot mounts seem to have more play.  If this is the case that should be easy to remedy by either employing Dhu Varrens suggestion, or by making the bogie holes in the coach bottoms narrower using some sort of thin shim or even paint to narrow the hole.  Will try this next week when I get some time.  Anyway its seems like an easy fix.

 

Top: MM 1st gen Craven (IR/IE) has different bogie to RPSI Craven - no wobble.

Middle: MM 2nd Gen Craven (CIE B&T livery) has the same bogie as RPSI, bottom RPSI Craven - no wobble.

Bottom: RPSI Craven - wobbles - bogie pivot has more play than 1st or 2nd gen MM Cravens

 

MM 2nd Gen Craven (B&T) + RPSI Craven are identical including bogies

 

Comparing bogies on IE/IR Craven, CIE B&T Craven + RPSI Craven.  You can see the bottom two are identical.

Edited October 21, 2017 by NoelG

[colmflanagan]

I have some Murphy Cravens coaches (CIE) and they run fine, but the system used by David  has worked well on a number of my coaches - even though I usually just put two strips on,  down each side of the bogie on one bogie only. This doesn't always completely eliminate "wobble" but cuts it down by 70% - ish - a big difference!  Older Airfix LMS coaches, which I use for LMS NCC variants, are particularly afflicted with wobble, as are some of the Hornby range.. Fortunately the coaches I chop up the most - the Mainline/Bachmann LMS 57' panelled LMS ones- do not seem to suffer from this issue, despite their plastic wheels and light weight!

o

olm

[NoelG]

Chatted with Paddy Murphy today and he has a fix for the RPSI cravens that will be available soon. It's a thin sprung brass shim that sits between the bogie and coach floor. The RPSI coaches were built with the same tooling but in a different factory.

[Georgeconna]

Got my pack today, not test ran yet. Upon mentioning the wobble to Mark of Marks Models he mentioned there is a remedy going to be issued by Murphy's to stick above the bogie to eliminate it. Fingers crossed. He mentioned different bogies were put on these ones as opposed to the orange ones.

 

Not sure how they are going to get these out to the punters though.

[NoelG]

Got my pack today, not test ran yet. Upon mentioning the wobble to Mark of Marks Models he mentioned there is a remedy going to be issued by Murphy's to stick above the bogie to eliminate it. Fingers crossed. He mentioned different bogies were put on these ones as opposed to the orange ones.

 

Not sure how they are going to get these out to the punters though.

 

 

They are very nice coaches.  Apparently they are selling well so it seems likely RPSI will release another set in the future with 3 standard coaches making a rake of six.  

[Georgeconna]

Just ran mine, Bit sloppy running wise but very nicely done.

 

Tried Propelling them around a curve, Ouch they dont like that either. 21 inch or R809 radius. Hope that 'fix' will sort that out too.

[NoelG]

Going to make an RPSI 3173 to run with my RPSI Cravens.  Got some brass sides from Mousa models for a BCK GSV (i.e. same as RPSI's maroon 3173 GSV).  Will use a Bachmann BCK donor rather than the Triang-Hornby in the pic.

 

[WrennEire]

Not sure if this will work?

 

[kirley]

Works fine Dave, impressive looking rake.

[NoelG]

The maroon GSV looks great with the RPSI Cravens.  Pity it is the 3185 BSK layout rather than the correct 3173 BCK door/window arrangement.  But looks great with the Munster Double rake (which we travelled on).  Dave, did you get the washer shims from PM to fix the RPSI craven wobble? (i.e. washers for the bogie pivots)

[kirley]

I got my set back in October but could not run it as one of the wheel sets was not insulated and caused a 'short' on my DCC layout. 

 

 

I had emailed PM a number of times and today out of the blue a envelope arrived containing this;

 

 

I replaced the offending wheel set and did a test run and everything was fine except for the wobble. 

 

 

I see Paddy included the 'sims' to address this issue but before I do anything can any one please advise on the correct way to remove the bogies?

 

[kirley]

Got my answer elsewhere, they are a snap fit.

[NoelG]

Get a decent vice grips out of the tractor toolbox, clamp the coach body firmly in a bench vice, then clamp the vice grips on the bogie, place a 1" chisel between the bogie and under frame, then give the chisel a belt with a block hammer and the bogie should fly off, but recommend tying some bailing twine to it beforehand so you don't lose it when it flies off!   (in jest - the real answer is below)

 

 

Just kidding Seriously the bogies just pull off by hand.  See real pic below.

 

Edited February 20, 2018 by NoelG

[kirley]

Tried out David Jackson's fix and it worked for two coaches but not the third.  I added washers to the other bogie on this coach and there is a good improvement.

 

[NoelG]

I do find it somewhat irritating that such expensive coaches could be shipped with a quality control defect as bad as this one. It matters little how good they look if they run like rubbish toys. There was a sprung washer fix demonstrated at the SDMRC show which seemed the only fix that works (i.e. a washer on its own does not work).  Despite the good intent and innovative suggested fix, modellers should not have to glue bits on to a €50 coach to make it run acceptably.

[Horsetan]

Probably academic if you're converting them to 21mm gauge, as you'd be going for sprung bogies, etc. anyway.