OO gauge GWR Mogul and Prairie

[melmerby]

8 hours ago, DavidCBroad said:

I swapped the Wrenn wheels for Hornby wagon wheels with the pin-points filed off,  With aB to B between 14.2 and 14.5 the go/ no go limitsbon my gauge these cured the derailments. My Dapol wheels are also more than 14.2 and less than 14.5mm B to B but  actually drop in on a one place on a curve.

It's not so much the B to B as the very thin flange, the Hornby flange is noticeably thicker and for the same B to B the Hornby has 0.5mm or more tyre on the opposite rail despite being about the same overall width.   I did try re profiling the Dapol tyres but they still derailed,

 

 

Are you sure your gauge is right as that looks a lot less than 14.2mm B2B?

This is my wheelset set to 14.2mm B2B sitting on Peco Streamline:

 

[St Enodoc]

1 hour ago, tomparryharry said:

This is going to sound somewhat controversial, but, it happens on the big railway as well. 

 

If you've got an unchecked rail , and a locomotive derails on  it , doesn't that tell you something? .......... ' Unchecked rail'....... That is why we used to call in the P.Way people, to install a check rail.  Check rails are bespoke; they can & do vary in length. Anything from 12', up to anything that a check rail is required.  If the loco was derailing on straight track, then your concern is- would be, completely justified.  If it's a localised problem, then deal with it at a localised level.  On a more, possible serious problem, modifying the model may well preclude said model from working over  a larger portion of the layout.  operating machinery (any scale/gauge ) outside of its design parameters will sometimes result in disappointment. If you peruse Youtube, you will see a Deltic spreading some points on the North Norfolk Railway.  We dropped a class 37 on the P&B  because of poor pointwork. 105 tons, mind.....

 

..... Unchecked rail.......

Assuming this is aimed at me, Tom, I agree entirely. However, the geometry of a 1 in 6 double slip in standard 00 is such that there is an area round the elbows (K crossings) that is effectively unchecked and not much can be done about it.

 

Without a) changing the springing on the pony truck to increase the centring force or b) a complete revamp to get rid of the cam pony pivot altogether, there's not much that can be done in this specific case. I'm not willing to try either of those things due to the risk (as you mentioned) of making something else worse, so the easy answer is to ban the loco from that particular section of track, which isn't a problem as far as operating the layout is concerned.

 

Regarding check rails in larger scales, back in about 1986 some track had been relaid over a weekend at Leeds City. Come Monday morning, a class 45 derailed at a crossover. It turned out that the newly-installed points had no check rails fitted...

[DCB]

@melmerby   Your wheels look to have a fatter metal stub axle than mine, is it stepped?  Mine is parallel.  I have a go / no go gauge. 14.2mm one end and 14.5mm the other. If a wheelset fits the 14.2 end and doesn't fit the 14.5 end then its generally fine.  The Dapol may have gone out of gauge but if it has the only way to get it back is to put super glue down the plastic axle muff.

For now I'll ignore the 8 instead of 10 spokes of the Hornby wheel. Plan B try Hornby Prairie wheels and if good wait for Peters Spares to get some in stock.  Shouldnt have to do it on a brand new "RTR" loco

[tomparryharry]

3 hours ago, St Enodoc said:

Assuming this is aimed at me, Tom, I agree entirely. However, the geometry of a 1 in 6 double slip in standard 00 is such that there is an area round the elbows (K crossings) that is effectively unchecked and not much can be done about it.

 

Without a) changing the springing on the pony truck to increase the centring force or b) a complete revamp to get rid of the cam pony pivot altogether, there's not much that can be done in this specific case. I'm not willing to try either of those things due to the risk (as you mentioned) of making something else worse, so the easy answer is to ban the loco from that particular section of track, which isn't a problem as far as operating the layout is concerned.

 

Regarding check rails in larger scales, back in about 1986 some track had been relaid over a weekend at Leeds City. Come Monday morning, a class 45 derailed at a crossover. It turned out that the newly-installed points had no check rails fitted...

 

Good Heaven no, young sir! Not in the slightest.  This is art copying real life, and your last paragraph sort of nails it.  The check rail is, by its nature, a highly bespoke item;  designed as a purely localised fitting to overcome a local problem.  My only suggestion is to design out the problem at a P. Way level. A lot of locations have gone through massive remodelling to plan out facing points and sometimes it happens miles away from the problem area, long before the location in question is reached. 

 

You can rest assured that I'm not 'having a go',  By way of ideas, might be a solution to solder two track pins onto a bit of offcut rail, and insert/install your own check rails. Thickness is not an issue here; the idea is to keep the wheel rim within gauge.  Check rails can be incredibly thin; nothing more than a sliver of tin can. Perhaps, a section of very thin Plasticard. 

 

I haven't unboxed my mogul yet. It sits on the shelf, looking at me. I know I'd be perplexed if one of my locomotives kept coming off the road. 

 

Best wishes,

Ian. 

[DCB]

Another vote for bespoke check rails.  I use them at baseboard joints where the lifting section lands, on some points in a vain attempt to keep a Hornby T9 on the rails and all the way around the return loop in the garden before I extended it.  

Edited April 10, 2021 by DavidCBroad

[melmerby]

4 hours ago, St Enodoc said:

 

 

Without a) changing the springing on the pony truck to increase the centring force or b) a complete revamp to get rid of the cam pony pivot altogether, there's not much that can be done in this specific case. I'm not willing to try either of those things due to the risk (as you mentioned) of making something else worse, so the easy answer is to ban the loco from that particular section of track, which isn't a problem as far as operating the layout is concerned.

 

 

What centring spring? Mine doesn't have one, it is free to move side to side as it wishes.

It does however have a spring to impart some downward pressure on the truck

As to the cam effect, I have just tried it on my tightest curve which is 30" and it hadn't reached the point at which the camming moves the pony truck forward.

It's only seems to come into effect for tighter trainset curves.

 

Edit

Both the front buffers have now fallen off, at least I still have them, unlike the smokebox dart which has vanished into thin air.

Edited April 10, 2021 by melmerby

[melmerby]

4 hours ago, DavidCBroad said:

@melmerby   Your wheels look to have a fatter metal stub axle than mine, is it stepped?  Mine is parallel.  I have a go / no go gauge. 14.2mm one end and 14.5mm the other. If a wheelset fits the 14.2 end and doesn't fit the 14.5 end then its generally fine.  The Dapol may have gone out of gauge but if it has the only way to get it back is to put super glue down the plastic axle muff.

 

2mm non-stepped axles as far as I can tell and I don't seem to be able to push them into the plastic muff to get less than 14.2mm back to back.

I can pull them apart but when I push them back together they get to a point where, without undue force, they stop and that is about 14.2mm

Edited April 10, 2021 by melmerby

[St Enodoc]

9 hours ago, tomparryharry said:

I know I'd be perplexed if one of my locomotives kept coming off the road.

Thanks Tom. Actually, I'm not perplexed at all - I know exactly what the problem is but the cure might be worse than the disease, so to speak. I'll live with my workaround (if it was happening on a different part(s) of the layout it would be a different story of course!).

[St Enodoc]

8 hours ago, melmerby said:

What centring spring? Mine doesn't have one, it is free to move side to side as it wishes.

It does however have a spring to impart some downward pressure on the truck

As to the cam effect, I have just tried it on my tightest curve which is 30" and it hadn't reached the point at which the camming moves the pony truck forward.

It's only seems to come into effect for tighter trainset curves.

 

Edit

Both the front buffers have now fallen off, at least I still have them, unlike the smokebox dart which has vanished into thin air.

My loose use of English, Keith. I meant adding more springing to provide a centring force, of which there is none at the moment. It's conceivable that the existing spring is actually preventing self-centring but as I've said I can live with my workaround.

 

I had the same problem with buffers and dart but fortunately I found them all and glued them in place.

[DCB]

9 hours ago, melmerby said:

2mm non-stepped axles as far as I can tell and I don't seem to be able to push them into the plastic muff to get less than 14.2mm back to back.

I can pull them apart but when I push them back together they get to a point where, without undue force, they stop and that is about 14.2mm

I pushed mine right in to a fraction under 14.2 and got sparks, the two stub axles touched and shorted the wheels out.  The plastic bit is just a sleeve.  I found the outside of the Dapol flanges match Hornby flanges when Hornby is at around 14.3mm and the Dapol wider than 14.5mm.  Its down to the thin Dapol flanges.  Plan B is  reprofiled tyres and the wheels set to 14.6mm  and super glued in place.    Next problem will be fitting Hornby Dublo couplings.

[melmerby]

6 hours ago, DavidCBroad said:

I pushed mine right in to a fraction under 14.2 and got sparks, the two stub axles touched and shorted the wheels out.  The plastic bit is just a sleeve.  I found the outside of the Dapol flanges match Hornby flanges when Hornby is at around 14.3mm and the Dapol wider than 14.5mm.  Its down to the thin Dapol flanges.  Plan B is  reprofiled tyres and the wheels set to 14.6mm  and super glued in place.    Next problem will be fitting Hornby Dublo couplings.

Maybe there is some plastic swarf in mine that kept them just apart?

I'm surprised you have had so much trouble with the pony truck, mine stays on the track without a problem. All track is Peco code 75 with Electrofrog pointwork, including double slips and three ways.

I normally set all B2B at 14.5, I find 14.2 too narrow (too much side to side movement), I was using 14.8 at one time, but the check rail gaps on Peco points need to be reduced and any stock set to less than 14.8 wont pass through them.

(If you use Romford/Markits driving wheels they are a loose 14.5mm B2B)

 

Why not get some wheels from one of the wheel firms? e.g. Alan Gibson.

Aftermarket wheels look so much better and the Dapol pony wheel tyres look too chunky.

Edited April 11, 2021 by melmerby

[tomparryharry]

Still thinking on this problem, let's start with the silly ones. Keith mentioned the Gibson wheels. I'd certainly agree on trying them.  With the RTR versions, try swapping out the pony truck wheelset, and changing them side-to- side.  While you're at it, and you have a vernier, put the vernier over the wheelset.  Dapol might be good, but their QC won't go down to pony truck wheel diameters, unless something is obviously wrong.  Also a bit silly, but try the model without the pony truck.... 

 

Have a look at the pony truck itself, and its relation to the truck, wheelset, and chassis. 

 

My earlier post regarding check rails needs some editing, so apologies from me.  If they do indeed short through, then insulation is the solution.  Sorry!  Insert the term 'might be....

 

To provide a centring device, it might be possible to install a thin piano-type wire which runs back from the centreline of the pony truck, back to the centreline chassis of the model. It shouldn't impart any sideways force, but 'encourage' the 'truck back to centre. 

 

However, if the pony truck is passing through a compound curve (where the direction of travel quickly changes from left to right ) then the normal big railway solution is the check rail, which is where I came in..... 

 

Have a great weekend,

Ian.

[melmerby]

7 hours ago, tomparryharry said:

To provide a centring device, it might be possible to install a thin piano-type wire which runs back from the centreline of the pony truck, back to the centreline chassis of the model. It shouldn't impart any sideways force, but 'encourage' the 'truck back to centre. 

 

Have a great weekend,

Ian.

I've done that on the rear truck of the Hornby Prairie.

I use Kadees and when reversing through a slight curve, Hornby's swivelling arrangement and all the slop makes the truck take up a very angular position, such that couplings don't line up at all.

With a light centering spring it follows a more prototypical course and it will couple on a slight curve.

Edited April 11, 2021 by melmerby

[DCB]

I think I cracked the pony truck/ wheel issue, I put the stub axle and wheel half in my black and decker drill chuck and reprofiled the tyre to have a conical profile a bit like the wrenn wheels.

Set to at least 14.6mm maybe 14.75 B to B and secured with superglue the wheels ran down a 1 in 100 gradient and round the curved route on a Peco code 100 3ft radius point .

The Hornby wagon wheels ran a lot less freely and stopped dead on the point as they tried to go straight 

With wheels refitted the loco then ran for 20 minutes, then when I demonstrated my success to my father in law the damned thing promptly derailed.  It then derailed again in the same place were it had previously run for twenty minutes.  Major panic, then the culprit was found, the Merchant Navy, Brand new, had shed its brake gear and the Mogul wouldn't climb over it.

The coned wheels self centre and take 2ft etc curves without the flanges coming in to play,

It seems the cam only works on trainset curves, and lets the wheels move forward to clear the cylinders. Even on 3rd Radius it doesnt seem to do anything, but I suspect it will cause issues hauling tender first or being double headed.

Its getting locked up solid first chance I get.

Edited December 18, 2021 by DCB

[tomparryharry]

2 hours ago, DavidCBroad said:

I think I cracked the pony truck....

Oh dear, I hope not!

 

Pleased to learn  that there might be a solution after all,; nice one! Once again, art is imitating real life.  I'm very interested to see how this turns out (pardon the pun ).

[Craigw]

For those inclined towards the P4 or EM path, I ordered a body shell and tender (as spares from DCC supplies) and they arrived yesterday. The body is complete and painted whilst the tender is a complete tender. As I have a separate chassis kit arriving soon, this is a far simpler approach.

 

Regards,

 

Craig W

[Rail-Online]

On 26/04/2021 at 21:04, Craigw said:

For those inclined towards the P4 or EM path, I ordered a body shell and tender (as spares from DCC supplies) and they arrived yesterday. The body is complete and painted whilst the tender is a complete tender. As I have a separate chassis kit arriving soon, this is a far simpler approach.

 

Regards,

 

Craig W

Craig,

 

You will be missing the cast boiler 'bottom' as this is not on the chassis kit.

 

Tony

[Adrock]

Hi, I think I recall reading something about this but am struggling to locate in this 95 page thread! Did someone say that they had programmed their DCC decoder with a completely new speed profile and curve, and had hugely improved the running as a result? If so, could anyone point me to the details at all please, as I’d like to replicate this! I have a ZIMO decoder fitted in mine. 
 

Thanks. 

[melmerby]

On 01/06/2021 at 14:37, Adrock said:

Hi, I think I recall reading something about this but am struggling to locate in this 95 page thread! Did someone say that they had programmed their DCC decoder with a completely new speed profile and curve, and had hugely improved the running as a result? If so, could anyone point me to the details at all please, as I’d like to replicate this! I have a ZIMO decoder fitted in mine. 
 

Thanks. 

I bought mine sans decoder and fitted my own (MX618N18) and had to profile it from scratch, it wasn't particularly easy due to the loco's inherrent characteristcs.

Edited June 2, 2021 by melmerby
wasn't instead of was

[Adrock]

On 01/06/2021 at 14:49, melmerby said:

I bought mine sans decoder and fitted my own (MX618N18) and had to profile it from scratch, it was particularly easy due to the loco's inherrent characteristcs.

Yes that’s the same decoder that I have. Are you able to read and share the CV values that you used at all? Or not easily?

 

thanks. 

Edited June 2, 2021 by Adrock

[melmerby]

2 hours ago, Adrock said:

Yes that’s the same decoder that I have. Are you able to read and share the CV values that you used at all? Or not easily?

 

thanks. 

A typo in my statement

It should've read "it wasn't particularly easy"

 

I found it a bit of a pig compared to most other locos I have done.

Do you use JMRI?

If so I have the Decoder Pro file for the loco.

Edited June 2, 2021 by melmerby

[Cofga]

Mine has a SoundTraxx Next18 steam decoder right now and it has a tendency to catch a touch once every rotation of the drivers. Mostly noticeable at slow speed when starting up. It also can’t pull much better than my Oxford Dean’s Goods, probably because the boiler is so light. I am thinking of gutting the electronics and wiring in an ECO-100 UK steam decoder and replacing all the extra electronics with moldable lead. I also am wondering how long that klutzy little connector between the tender and loco will last. I expect that little clip to pop off every time I disconnect it. Hopefully the Waingwright 4-4-0 will not repeat all these mistakes. I now have a collection of 11 UK steam locos and the Bachmann 0-6-0PT’s are the best runners and cheapest among them. 

Edited June 3, 2021 by Cofga

[melmerby]

1 hour ago, Cofga said:

Mine has a SoundTraxx Next18 steam decoder right now and it has a tendency to catch a touch once every rotation of the drivers. Mostly noticeable at slow speed when starting up. It also can’t pull much better than my Oxford Dean’s Goods, probably because the boiler is so light. I am thinking of gutting the electronics and wiring in an ECO-100 UK steam decoder and replacing all the extra electronics with moldable lead. I also am wondering how long that klutzy little connector between the tender and loco will last. I expect that little clip to pop off every time I disconnect it. Hopefully the Waingwright 4-4-0 will not repeat all these mistakes. I now have a collection of 11 UK steam locos and the Bachmann 0-6-0PT’s are the best runners and cheapest among them. 

There seems to be a trend to make locos too light and use underpowered motors.

The old Hornby 5101 Tank (updated Airfix) is more than 100g heavier than the new one, as unlike the new one all the space in the tanks is full of metal, a feature I have replicated by filling my couple of new ones full of lead sheet.

The problem with doing that in the Dapol 43XX is that the motor is not particularly strong.

Mine was slipping with six Hornby Colletts when going up my 1:100 incline, so I put a saddle of lead over the boiler to help adhesion. It stopped the slipping but the loco slows noticably up the incline.

A Bachmann 0-6-0PT manages it with ease.

[Adrock]

On 02/06/2021 at 17:30, melmerby said:

A typo in my statement

It should've read "it wasn't particularly easy"

 

I found it a bit of a pig compared to most other locos I have done.

Do you use JMRI?

If so I have the Decoder Pro file for the loco.

I did wonder whether it was a typo or not! No I don’t use JMRI, haven’t needed to on any loco other than this loco potentially!

[The Johnster]

On 03/06/2021 at 23:01, melmerby said:

There seems to be a trend to make locos too light and use underpowered motors.

The old Hornby 5101 Tank (updated Airfix) is more than 100g heavier than the new one, as unlike the new one all the space in the tanks is full of metal, a feature I have replicated by filling my couple of new ones full of lead sheet.

The problem with doing that in the Dapol 43XX is that the motor is not particularly strong.

Mine was slipping with six Hornby Colletts when going up my 1:100 incline, so I put a saddle of lead over the boiler to help adhesion. It stopped the slipping but the loco slows noticably up the incline.

A Bachmann 0-6-0PT manages it with ease.

One of my soapboxes.  I habitually cram as much ballast as I can in above the driving wheels and it always improves the loco’s haulage ability and the contact of the wheels to the railhead, and the running in consequence.  My current method is to make a mix of Milliput and Liquid Lead. As all my locos are steam outline tank types, there is usually space in the tanks and at the top of the boiler space, being careful not to foul the gears and leave space for air to circulate around the motor, and most models will benefit from filling the inside of the smokebox. 
 

As my layout is a small BLT, loads are light and haulage not an issue, but ballasting of this sort is worth it for the improved running.