RPSI /MM Cravens

[WT CLASS 2-6-4T No. 4]

Does anyone else have trouble with the running of the new RPSI Craven coach. Inclined to wobble when running. Any cures appreciated.

[Noel]

Well spotted WT Class 2-6-4T No 4. However I've just spent a while examining the three craven variants and discovered the later MM Craven bogies and the RPSI craven bogies are identical. MM first batch of Cravens were IR/IE 'tippex' livery dual white stripe livery, but the later batch of CIE Black'n'Tan Cravens (single white stripe at roof level) had different bogies and corrected shorter NEM pockets. The RPSI coaches also have these later bogies with the shorter NEM pockets.

 

Monty Python's quest for a solution to wobbling Cravens.

• RPSI Bogies are identical to later MM Cravens
  
• MM Cravens and RPSI Cravens weigh the same
  
• Wheel sets appear to be the same on all three
  
• RPSI bogies seem to have more play (i.e. pivot hole)
  

 

PS: None of the real cravens wobbled on the excellent RPSI Munster Double rail tour last weekend. Much more comfortable than any of the ICRs. :)

 

Photo One: Top to bottom: 1st batch MM Cravens IE/IR, 2nd batch CIE B&T, 3rd batch RPSI (identical). The bottom two have the same bogie sides (checked spurs for same tooling).

 

The only difference I can find is that the RPSI bogie pivot holes have more play than either of the two MM variants. Will investigate Dhu Varrens excellent suggestion and also a method of reducing the diameter of the holes for the bogie snap in pivot hinges.

 

Photo Two: Identical Bogies on later MM B&T CIE and recent RPSI Cravens

 

Photo Three: Bottom two coaches physically identical

 

I've just spend the last hour testing all my MM Cravens running and none of them wobble like the RPSI/MM Cravens!!! Tis just one of life's little mysteries

 

I think this is going to be easy to fix with some sort of shim or even tick paint narrowing the pivot holes in the coach undersides to reduce play.

[Dhu Varren]

Here are the pictures that could not be uploaded earlier.

I have used white plastic so that the strips show up clearly against the black underframe, but a quick coat of black paint would soon hide them.

 

[Noel]

Does anyone else have trouble with the running of the new RPSI Craven coach. Inclined to wobble when running. Any cures appreciated.

 

Yes, same with my set.

[Northman]

Think I'll wait and see if the 'wobble' can be fixed before I order.

[craven1508]

waiting may not be an option? probably sell out. this will restrict speed on your layout!

pity this has happened in the mist of all the excitement!!!!!!

[roxyguy]

My cravens wobble at the best of times. Must a be a slight flaw in some of them.

[Noel]

Think I'll wait and see if the 'wobble' can be fixed before I order.

 

I wouldn't wait, they are truly superb coaches and bound to be popular. The wobble is a relatively minor issue which I'm sure should be easy to rectify.

[WT CLASS 2-6-4T No. 4]

I think that the cause of the wobble is that the bogies on the rpsi version are different to the bogies on the original mm version.

[RedRich]

No thinking about it you are spot on as they are two completely different bogies with the original being much closer to the prototype. The bogies on the RPSI models are wrong in so many areas. Looking at the RPSI models the bogies look like the bogies on the MM MK11 aircon models. Otherwise a superb looking model the livery application looks good.

 

Rich,

[NIRCLASS80]

Also the buffers stick out more meaning on small and medium radius curves buffer locking can occur.

[Dhu Varren]

*

Edited October 20, 2017 by Dhu Varren

[Dhu Varren]

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.

Edited October 21, 2017 by Dhu Varren

[Dhu Varren]

This site is really playing up tonight. Won't insert pictures, and won't let me edit posts correctly.

Edited October 20, 2017 by Dhu Varren

[Garfield]

Hi Dhu Varren,

 

Apologies. There may be temporary glitches and errors while we're conducting upgrades to the forum's servers:

 

http://irishrailwaymodeller.com/showthread.php/6532-Maintenance-Work?p=104621#post104621

[Broithe]

Should have done it on Monday and blamed Ophelia.

[Garfield]

Should have done it on Monday and blamed Ophelia.

 

We're blaming Brian

 

https://www.irishtimes.com/news/ireland/irish-news/storm-brian-flooding-fears-for-coastal-areas-as-sandbags-put-out-1.3262968

[Broithe]

We're blaming Brian

 

https://www.irishtimes.com/news/ireland/irish-news/storm-brian-flooding-fears-for-coastal-areas-as-sandbags-put-out-1.3262968

 

He's just a naughty boy.

[WT CLASS 2-6-4T No. 4]

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.

 

Thanks Dhu Varren, looking forward to the pics when you get to upload them.

Wally.

[John-r]

Ha , Noel great minds think alike, I did the same as you lined up all the cravens and noticed the difference in the bogies, I then swapped over wheels from an rpsi coach to a standard craven now

admittedly I only run my finger along the wheels, but I saw no wobble on the rpsi coach when wheels were changed then changed

back to original rpsi wheels and wobble was back, as I say I had no track to try this on but i saw a difference. Just to add still glad I got this lovely set of coaches and would in time like to see the

remaining coaches released. Well done rpsi.

[RedRich]

On 10/20/2017 at 7:34 PM, hexagon789 said:

I can PM or e-mail you the article if you like, whichever is more convenient. Be warned it's my first article so it's rather long and wordy! I can also give you a fairly exhaustive list of formations to go with it as well if you care for it.

 

Edited October 21, 2017 by RedRich

[RedRich]

Don't know how that last post appeared gents. Its a strange one that the bogies have changed from the original released IR IE liveried coaches to the B&T and RPSI releases. I like the original released B4's as they are almost identical to the Bachmann bogies on the MK2A's.. Personally  I love the replica railways B4 bogies they really capture the look. I'd definitely get rid of the bogies and replace them because they let down what is an otherwise cracking model.

Rich,

 

[Noel]

Attempt using washer to remove RPSI Craven Wobble failed. 

I made 120 plastic card shim washers and fitted them, perhaps 115 might have been better. Unfortunately they did not improve the wobble one iota.    Will try MMs washers when they become available but not optimistic based on my experiment with a plastic washer.

Yes the RPSI craven bogies are harder to remove, as somebody suggested it must be a harder plastic, flat screwdriver underneath helped prise them off by hand.

Shim washer cut from 120 plastic sheet - perhaps 115 might have been better, but I filed it a bit thinner anyway.

This had no effect whatsoever on the RPSI Craven Wobble.