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OO gauge GWR Mogul and Prairie


Paul.Uni
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9 hours ago, St Enodoc said:

I have two double slips and two single slips on the layout (scratchbuilt in code 75 bullhead). My Mogul runs well through all of them except for one straight route on one double slip in one direction, when it derails by taking the wrong road at the elbow. Solution: bar the loco from that goods yard.

 

I wonder whether the spring/cam arrangement is causing a slight bias to the right. If it starts to happen elsewhere I might try lubricating the slides as suggested in the manual.

I have also started having problems running the Mogul on part of the layout where the front bogie jumps the rails.  This has only started occurring recently.   It happens at two points a double slip when it takes the right hand fork  and on a slight right hand curve.  I checked and amended the back to back - did not cure the problem.  I lubricated the slides, did not help.  I tried to remove the whole bogie to have a closer look, but gave up when I was not sure how to disconnect the spring (without forcing it and breaking it).  I think you might be right St Enodoc and the spring/cam has a bias (which I possibly made worse when I weathered and then cleaned the wheels of the loco).

 

In desperation I replaced the bogie wheels with finer scale replacements.  Now runs perfectly.  My point work is Marcway 00 gauge code 75 and track is SMP.       

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44 minutes ago, TheSignalEngineer said:

I had the same issue with the close coupling cams on some Hornby coaches.

I had the same problem on some Hawksworths. A few strokes of a sanding stick on the part that the coupler mount rubs against cured that.

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28 minutes ago, Gopher said:

In desperation I replaced the bogie wheels with finer scale replacements. 

That's interesting. Some Dapol wagons, especially 6-wheel milk tanks, are notorious derailers. I have heard that this is due to a poor wheel profile, which is quite plausible. Replacing the wheels with Hornby, for example, cures the problem. I'll see whether I've got a suitable replacement wheelset. Thanks.

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27 minutes ago, St Enodoc said:

That's interesting. Some Dapol wagons, especially 6-wheel milk tanks, are notorious derailers. I have heard that this is due to a poor wheel profile, which is quite plausible. Replacing the wheels with Hornby, for example, cures the problem. I'll see whether I've got a suitable replacement wheelset. Thanks.

I've found a very ancient Gibson 3' 2" 10-spoke bogie wheelset in my spares box (price GBP 1.80 from Puffers at Kenton). The axle seems to be a perfect fit in the Dapol pony truck, so tomorrow I'll make up the wheelset (my wheel press aka vice is outside in the garage) and try it out. I'll report back.

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19 hours ago, St Enodoc said:

I've found a very ancient Gibson 3' 2" 10-spoke bogie wheelset in my spares box (price GBP 1.80 from Puffers at Kenton). The axle seems to be a perfect fit in the Dapol pony truck, so tomorrow I'll make up the wheelset (my wheel press aka vice is outside in the garage) and try it out. I'll report back.

The replacement wheelset made no difference whatsoever, so I took it out and put the Dapol one back in. Never mind - nothing ventured, nothing gained.

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2 hours ago, St Enodoc said:

The replacement wheelset made no difference whatsoever, so I took it out and put the Dapol one back in. Never mind - nothing ventured, nothing gained.

Sorry to hear that.  It is all trial and error with these things.  I am convinced there is some anomaly with the cam/spring.  I have had three of these locos (first two electrical faults), but they all ran well over all my point work.  I have no idea why my current model suddenly developed a problem with the front bogie.  All I can think off is whilst man handling it for weathering/cleaning  I disturbed the bogie in some way.  I think it could do with a stronger spring.  

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On 15/01/2021 at 16:45, The Stationmaster said:

And going from your suggestion how about this -

 

danycoed.jpg.deac4e78f847f2355eeca950b6e2e1a4.jpg

 

 

 

Similar, but not sure the woods match. The valley side in the other pic is very steep.

 

Shouted M&M to me, classic 1950s  train formation. There's a pic of 6375 at Conwil on:

http://www.disused-stations.org.uk/c/conwil/

 

My guess looking at the maps would be that the pic is taken at SN 3874 2613 looking ESE; the hillside on the north side of the valley at that point is very steep and the woodland ends at just the right point.  Just a tad SE of Conwil station after the river crossing.

 

Nigel

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21 hours ago, Gopher said:

Sorry to hear that.  It is all trial and error with these things.  I am convinced there is some anomaly with the cam/spring.  I have had three of these locos (first two electrical faults), but they all ran well over all my point work.  I have no idea why my current model suddenly developed a problem with the front bogie.  All I can think off is whilst man handling it for weathering/cleaning  I disturbed the bogie in some way.  I think it could do with a stronger spring.  

Following some suggestions on my layout topic, I tried pushing the back-to-back out to 14.7mm but it made no difference, so I looked more closely. The approach to the problem area is on a right-hand curve. Where it straightens out to cross the slip the pony truck stays over to the right, so it takes the wrong road at the elbow point rails, which due to the geometry are to all intents and purposes unchecked. Consequently, I didn't bother pushing the wheels out any further (14.85m had also been suggested) as that might cause other problems elsewhere.

 

The solution, if I can be bothered, will be to dismantle the pony truck altogether and rebuild it without the cam arrangement. In the meantime, I will live with it.

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1 hour ago, St Enodoc said:

Following some suggestions on my layout topic, I tried pushing the back-to-back out to 14.7mm but it made no difference, so I looked more closely. The approach to the problem area is on a right-hand curve. Where it straightens out to cross the slip the pony truck stays over to the right, so it takes the wrong road at the elbow point rails, which due to the geometry are to all intents and purposes unchecked. Consequently, I didn't bother pushing the wheels out any further (14.85m had also been suggested) as that might cause other problems elsewhere.

 

The solution, if I can be bothered, will be to dismantle the pony truck altogether and rebuild it without the cam arrangement. In the meantime, I will live with it.

Thanks for the update that is exactly how my loco behaved at one of my double slips.  I also tweaked the back to back (made it wider and slightly narrower) - did not help.  I thought I might remove the cam and spring, but gave up when I was not totally sure how to disengage the spring from the loco body.  It looks as if it might be secured by a small nut, or a push on gromet.   I am not totally sure why changing the bogie wheels on my loco cured the problem - but I quit while I was ahead.   I ran it yesterday (to make sure it was not some kind of fluke). It is still behaving, and it appears to me compared to the original wheels (might be my imagination ), that the new wheels are now almost stuck to the track.   They are a bit lighter and finer profile tyres, but the cam seems to work well with them and they follow the track geometry very precisely.    Hope you do find a solution.  

 

 

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2 hours ago, Gopher said:

  I am not totally sure why changing the bogie wheels on my loco cured the problem - but I quit while I was ahead.   I ran it yesterday (to make sure it was not some kind of fluke). It is still behaving, and it appears to me compared to the original wheels (might be my imagination ), that the new wheels are now almost stuck to the track.   They are a bit lighter and finer profile tyres, but the cam seems to work well with them and they follow the track geometry very precisely.    Hope you do find a solution.  

 

 

My mogul suffers from the same derailing problem with a bias to the right.  Inspection of the bogey LH wheel (looking forward) showed the wheel and tyre as oval.  A micrometer checked confirmed this.  It also suffers from a slack loco to tender connection.

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8 minutes ago, tarifa said:

My mogul suffers from the same derailing problem with a bias to the right.  Inspection of the bogey LH wheel (looking forward) showed the wheel and tyre as oval.  A micrometer checked confirmed this.  It also suffers from a slack loco to tender connection.

That is interesting about the wheels.  I run DCC sound (speaker in the tender)  the tender connection has deteriorated as I have uncoupled the tender frequently to try and sort out the bogie problem.  So the sound kept disappearing momentarily as the loco went over pointwork or uneven track.  I think I have cured this by smearing electrical grease on the plug, and prising the contacts in the socket so they sit up a bit more.  I then packed the socket with electrical grease.  I now intend to leave the loco and tender permanently coupled.     

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1 hour ago, boxbrownie said:

Is there any room under the truck to add some “liquid lead” weight?

 

Might help.

Thanks - I think this may be possible if you can get the bogie truck off the loco.  This was on my list of things to try.  I think there is some room where you could add a small amount of liquid lead which would not be visible.     

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Check that the approach to the offending slip is level and the piece is smoothly connected to the adjoining track, as any discrepancy here will mean that the pony flange approaches the elbow joint rail at less than an ideal angle, and takes off in the wrong direction.  You might cure this by lessening the b2b, but this is likely to cause problems elsewhere.  If the track is not perfectly laid, bad news; you'll have to take the whole junction out and relay it, which will mean deep cleaning the track bed and possibly replacing turnouts and slips, unless you can persuade your mogul to run reliably through the junction.  If you can't find anything wrong with the tracklaying, you can indulge in a sigh of relief and concentrate on the loco.  Don't assume that track laid perfectly has not moved in the meantime, or that the baseboard has remained in it's original level condition; all sorts of minor movement may have taken place under the stress of no more than tempeeratiure changes; even if your erection is permanent it's no good if it wobbles or sags...

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With regards wayward pony trucks: having studied the pony truck on my Dapol Mogul it is apparent that there is a significant amount of side play in the truck's wheelset.  When this is compounded with the amount of side play between the wheelset and the track then even when the locomotive is supposedly travelling in a straight line the pony truck's frame can still be significantly off centre to the point that the wheels may be aligned with the deviating route at the 'K' crossing, hence they are jumping the crossing.  There are a couple of things you might try to overcome this tendency. 

 

The first thing I'd recommend is using washers to eliminate the wheelset's side play in the pony truck's frame.   The wheelset simply clips into the pony truck and can be easily removed by using a small screw driver to lever the axle out of the slot, or you can pull the wheels apart as you are going to have to pull the stub axles out of their muff to fit the washers anyway. 

 

If this still doesn't sort it then the only other thing I can suggest is to add some side control but not if your model has to negotiate curves of less than 2' 6" radius.  The side control wire needs to be fine and springy - I use phosphor bronze wire when I do it.  The wire needs to be anchored centrally at the pivot end and act below the axle towards the front of the pony truck.  If the wire acts above the axle line then it has a tendency to lift the wheel that is on the outside of a curve increasing the risk of its derailing.  The side control wire should keep the wheelset pointing forwards on straight track.

 

The only model I have to hand at the moment to illustrate this has side control on the trailing axle but the method is identical.    

IMG_3147.jpg.dd69b13512b69ad35a5392237e920dc1.jpg

 

Regards,

 

Frank

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Tonight I rechecked the B2B and that the stub axles were evenly inserted into the sleeve as this can cause the wheelset not to lie centrally in the pony truck when running. There didn't seem to be anything stopping the pony truck from moving freely from side to side. Following tweaking the point blade, incidentally the mogul was the only loco to derail there. I test ran it through every point on the layout at slow and normal operating speed in the facing direction. I didn't get one derailment. Let's see what tomorrow brings.

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On 18/01/2021 at 12:13, Gopher said:

That is interesting about the wheels.  I run DCC sound (speaker in the tender)  the tender connection has deteriorated as I have uncoupled the tender frequently to try and sort out the bogie problem.  So the sound kept disappearing momentarily as the loco went over pointwork or uneven track.  I think I have cured this by smearing electrical grease on the plug, and prising the contacts in the socket so they sit up a bit more.  I then packed the socket with electrical grease.  I now intend to leave the loco and tender permanently coupled.     

That's quite interesting. I might just create a simple hook and loop connection as I think when mine is doing its' work with a load of (8?) Mk1s or whatever the Devonian was in December 1961, I wondered if the loco tender connection may not be adequate as a Drawbar. I haven't been up to check but if the loco needs a Fall-plate I might try to make that with some sort of drop in pin on the FP, with a suitable groove in the tender front floor plate? I'll see what the existing link does before bothering.

P

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13 hours ago, Mallard60022 said:

That's quite interesting. I might just create a simple hook and loop connection as I think when mine is doing its' work with a load of (8?) Mk1s or whatever the Devonian was in December 1961, I wondered if the loco tender connection may not be adequate as a Drawbar. I haven't been up to check but if the loco needs a Fall-plate I might try to make that with some sort of drop in pin on the FP, with a suitable groove in the tender front floor plate? I'll see what the existing link does before bothering.

P

I think the connection is quite clever and unlikely to come apart easily, although 8 Mk 1s on a gradient will be a test. 

 

It is  definitely a weak point electrically.  I think will deteriorate especially if you disconnect it frequently. I guess if you run DC all you lose is the tender pick up and may not notice.  Similarly if you run DCC sound but with a speaker in the loco.            

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Not sure if this has been posted before or not, but Dapol are reviewing the first EP of the prairie. Nice to see it has a die cast footplate. May well have the edge on haulage over Hornbys. Interesting to read they have allowed for future variations in the form of 3100, later 5100, and 8100 classes. 

8962359C-E788-4482-9680-6668238BB796.jpeg

Edited by Hilux5972
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4 hours ago, Hilux5972 said:

Not sure if this has been posted before or not, but Dapol are reviewing the first EP of the prairie. Nice to see it has a die cast footplate. May well have the edge on haulage over Hornbys. Interesting to read they have allowed for future variations in the form of 3100, later 5100, and 8100 classes. 

8962359C-E788-4482-9680-6668238BB796.jpeg

Is it just me, or does it look like Dapol have fixed the slide bar issues from the Mogul?

Might have to reconsider my pre-order on the latest batch of Hornby models.

Edited by DRoe96
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21 minutes ago, DRoe96 said:

Is it just me, or does it look like Dapol have fixed the slide bar issues from the Mogul?

Might have to reconsider my pre-order on the latest batch of Hornby models.

I think you are correct.  I wonder if they have sorted out the gearing as well?

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There's a danger Dapol might get themselves mixed up (again) with their prototypes. The upper part of the blurb says ".. shall be manufacturing these models from the early 1930s when cab side shutters were added" but the lower part of the blurb says "With and without cab shutters". In any case, there is a fairly small time window for locos not initially having cab shutters.

 

The tall safety valve cover is a nice feature, but applicable only to 20 locos - 5101–5110 and 5150–59.

 

I'm surprised but pleased to see the new slidebars, if indeed these are to be representative of production, but in a way it makes what appeared on the Mogul less excusable.
 

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I saw that Dapol tweeted that some of thier staff are now returning to site so pinged them off an email asking if there is any update on the DCC sound fitted model. Here is their reply: 

 

The models are being fitted in the UK by  our service provider, once they are ready they will be sent out to stockists. We are currently waiting for an update from our service provider. 

 

Good to know that they are still in the way just a little more patience needed.

 

Cheers 

 

Pete

 

 

 

 

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34 minutes ago, Miss Prism said:

 

 

I'm surprised but pleased to see the new slidebars, if indeed these are to be representative of production, but in a way it makes what appeared on the Mogul less excusable.
 

 

Alternately they've learned from a mistake.....

 

Just a thought

Les

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6 hours ago, Hilux5972 said:

Not sure if this has been posted before or not, but Dapol are reviewing the first EP of the prairie. Nice to see it has a die cast footplate. May well have the edge on haulage over Hornbys. Interesting to read they have allowed for future variations in the form of 3100, later 5100, and 8100 classes. 

 

Doesn't the Mogul?

If not that's another inexcusable omission.

Getting sufficient mass with a large tank loco is easy, less so with a tender engine, so more metal is desirable.

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