OO gauge GWR Mogul and Prairie

[Adrock]

Running quality:

 

Have finally had chance to put a small temporary circuit of test track down on the garage floor (carpeted). Running seems pretty smooth and quiet to me on DC using a Gaugemaster controller. There is maybe a perceptible tight spot when crawling at the slowest speed - however, it doesn't seem to have anything to do with pickup of current because providing a bit more juice picks the engine up. I never had to prod it once. I really was testing this at very slow crawling speed, as a few people in the thread seemed most interested in this. What I cant say for sure is how my Bachmann engines respond at similar crawling speeds on the same testbed set up. I have taken some videos - will upload them if size permits.

 

 Note...videos are too big, I’ll try and find a way to compress them over next few days.

 

I ran light engine, both directions, and I added the Aberystwyth portion of the CCE for haulage tests (four x Bachmann mk1s, weight removed in three of them; Hornby Roco style close couplers). Seemed to handle this load without a problem. I looked for and couldn't detect any "opening" of the tender drawbar connection - there was probably more opening of the mk 1 coach cams under their own weight of the coaches.

 

Paint finish:

 

As mentioned by a few others, there is real sheen to the boiler that makes this look metallic. See pictures for comparison with Bachmann engines (all others are Bachmann). Lighting is natural but there is a little glare from the window into the cabinet as you can see. 

 

 

 

 

 

Edited November 17, 2020 by Adrock

[Harlequin]

30 minutes ago, Chuffer Davies said:

According to J.H.Russell the moguls were a tender version of the 31xx prairies

 

GW standardisation in action.

 

Not only does Russell say that, Holcroft the man who drew up the design, says, "Although no thought of it had entered into the decision what had been achieved was a tender engine edition of the '3150' class 2-6-2 tank."

 

Edited November 17, 2020 by Harlequin

[The Johnster]

The bend in the slide bars is clearly unprototypicat and may not be needed.  There is in the photos plenty of clearance for  the connecting rods, shown at the extremity of their vertical range at this point in the photos with the driving wheel crankpins at the 12 o'clock and 6 o'clock positions.  There would be less clearance if the slide bars were bent straight (can you say that?) but if you assume there is no or minimal distortion in the photo and run a straight edge along the slide bars It shows that the connecting rod still has a smidge of clearance, and this is a case in which a miss is as good as a mile.  But, this does not take into account any vertical play that there may be in hte centre axle, which, if it is provided, would probably generate contact between the connecting rod and the slide bars at the 12 and 6 o'clock positions, even with very minimal vertical movement of the centre axle.

 

What happens when the piston is fully extended, with the driving wheel crankpins at the 3 o'clock postion and in piston terms at bottom dead centre; perhaps more accurately referred to a right hand dead centre for left hand piston in this case?  It looks to me as if, with this degree of bend in the slidebars, there is nothing to keep the crosshead from 'coming off the rails' so to speak, and the piston rod emerging from the rear cylinder cover.  I've had this happen to an old Airfix large prairie as a result of one of the slide bars snapping, and you don't want to do this; the slow comede somersault as the piston rod drives into the ground and lifts the loco into the air before depositing it from height onto a per way hut, which was just as destroyed as it would have been if you'd dropped a real large prairie on a real per way hut, would do a highly detailed and delicate model of this sort no good at all!

 

On the Airfix type chassis, the crude crossbar holds the connecting rod well behind the slide bars and clear of any such contact (just!).  The plastic slide bars, the weak point of this model, have a representation of the chamfer but not the cutouts.  The compromises necessary for 00 mean that the prototypical arrangement cannot be copied, as the frames and thus the driving wheels are further than scale away from the slide bars assuming the slide bars are in the correct position relative to the overall scale width of the loco and the cylinders are correctly positioned.  There may well be a compromise here, though, as a 00 gauge model with the cylinders 'correctly' positioned may look propertionally too wide when the locos is viewed head on.  There are clearance issues with cylinders on Churchwardian locos and it may be that Dapol have used the 00 gauge compromise to lessen width over the cylinders a smidge to presevere clearance between the specified set track radius (2nd?) with the appropriate radius curved platforms. 

 

Whatever compromise Dapol have settled for, Hornby will have had the exact same issue with the recent large prairie, and perhpas have solved it in a different way.  This has ramifications for my future large prairie, as I have not yet decided between Hornby or Dapol.  It has to be said that Dapol have produced a very effective mogul at the price, and I am hopeful for their prairie, but the comments above on the subject of poor gear ratios and fast running, coupled with Sam's comment about slow running, are putting the red box model in the lead at the momen.  Slow running, and smooth starts and stops, with DC control are of very high importance on my layout, and might well ultimately swing the balance in favour of the Hornby, and misshapen slide bar will not help the Dapol; now I'm aware of them it's the first thing I'll be looking at on production prairies.  I suspect that I will be in a position to spend money on a prairie in about a year's time after  the 'hit' of the Bachmann 94xx on this poor old pensioner, and if the Dap prairie is not yet available by then, and it well might not be with the Manor being prioritised if my expectations are correct, then Dap will have lost the contest due to poor gearing and bent slide bars, which will be a shame but not something that will cause me any grief!  Bent slide bars can be straightened with pliers and brutality, but gear ratios need replacement chassis to address...

 

As to firebox glow, which is presumably on all the time under DC control, I rather hope it isn't too bright!  It should, IMHO, not really be noticeable under normal 'daylight' conditions, but I do run low light sessions to simulate the South Wales climate and early morning or evening light, and one ought I think to be aware of firebox glow in these conditions.  The upcoming 94xx, which is I believe somewhere on the high seas as I write, also has this feature and I will be disconnecting it or toning it down if I can see it in daylight.  There is unfortunately a tendency for RTR firms to produce locos with this sort of feature and make it overbright to show it off, which is understandable but not quite in line with what happened in real life.  Bright glow could certainly be seen when a loco was working hard, trying to accellerate up a bank for instance, but most of the time was less bright and conspicuous, and duller in colour.  Toning down can be achieved with paint, and I have done this to a lot of my lighting on the layout to achieve an effect closer to my memory of lighting in the 50s and 60s, with feeble filament bulbs.

Edited November 17, 2020 by The Johnster

[The Johnster]

36 minutes ago, Adrock said:

I really was testing this at very slow crawling speed, as a few people in the thread seemed most interested in this. What I cant say for sure is how my Bachmann engines respond at similar crawling speeds on the same testbed set up. I have taken some videos - will upload them if size permits.

Much appreciated Adrock, thank you for this. 

[melmerby]

59 minutes ago, Adrock said:

. I have taken some videos - will upload them if size permits.

 

 Note...videos are too big, I’ll try and find a way to compress them over next few days.

Hi

You can't upload videos.

You'll have to upload to a video sharing site and post a link to them.

[Chuffer Davies]

29 minutes ago, The Johnster said:

Bent slide bars can be straightened with pliers and brutality, but gear ratios need replacement chassis to address...

 

A word of warning.  If the slide bars on the Dapol Mogul are made of Mazak then it is highly likely that any attempt to straighten them will result in their destruction.  I learnt the hard way on my Heljan 47xx.  

 

Frank

[The Johnster]

Very good point, Frank.  One would not have thought that Mazak was a particularly suitable material for slide bars, but as mentioned Airfix and subsequently Hornby used plastic, which is wholly unsuitable IMHO.  I'd prefer producers avoided Mazak altogether, but that's not going to happen!  Surprised to hear of it being used for slidebars on the Heljan 47xx, though; a material not noted for it's sliding attributes...

 

An attempt to straighten a Mazak slide bar would result in it's shattering like crispy bacon!

[Joseph_Pestell]

11 minutes ago, The Johnster said:

  I'd prefer producers avoided Mazak altogether, but that's not going to happen! 

 

Accurascale are not using it despite bringing out their locos at very competitive prices.

[The Johnster]

Kudos to Accurascale!  Now, if I can just persuade them to produce a 2721 or Collett 1938 31xx, or both...

[MikeParkin65]

2 hours ago, The Johnster said:

 

As to firebox glow, which is presumably on all the time under DC control, I rather hope it isn't too bright!  It should, IMHO, not really be noticeable under normal 'daylight' conditions, but I do run low light sessions to simulate the South Wales climate and early morning or evening light, and one ought I think to be aware of firebox glow in these conditions.  The upcoming 94xx, which is I believe somewhere on the high seas as I write, also has this feature and I will be disconnecting it or toning it down if I can see it in daylight.  There is unfortunately a tendency for RTR firms to produce locos with this sort of feature and make it overbright to show it off, which is understandable but not quite in line with what happened in real life.  Bright glow could certainly be seen when a loco was working hard, trying to accellerate up a bank for instance, but most of the time was less bright and conspicuous, and duller in colour.  Toning down can be achieved with paint, and I have done this to a lot of my lighting on the layout to achieve an effect closer to my memory of lighting in the 50s and 60s, with feeble filament bulbs.

I've just bought the latest J72 which has the glowing firebox feature. I couldnt test it on DC due to its motor vocally expressing dislike of my Hornby trainset controller - purchased for test purposes. DCC fitted the glow is VERY subtle  - in fact initially I thought it wasnt working. If the 94xx is the same I wouldnt worry.

 

Worst firebox glow is surely the Rails Terrier - looks more like an AA van on motorway rescue than a coal fire!

[melmerby]

1 hour ago, The Johnster said:

Very good point, Frank.  One would not have thought that Mazak was a particularly suitable material for slide bars, but as mentioned Airfix and subsequently Hornby used plastic, which is wholly unsuitable IMHO.

 

And Mainline → Bachmann.

 

Grafar used round steel rod on the 81XX and no piston rods IIRc.

HD used pressed steel with plating.

[melmerby]

1 hour ago, Joseph_Pestell said:

 

Accurascale are not using it despite bringing out their locos at very competitive prices.

Mazak is fine when used just for adding mass but not ideal for constructional parts

 

We could always go over to using Tungsten!

I found a place that sells Tungsten in small blocks which could be useful for weights. You need to buy in quantity though

[spamcan61]

2 minutes ago, melmerby said:

Mazak is fine when used just for adding mass but not ideal for constructional parts

 

We could always go over to using Tungsten!

I found a place that sells Tungsten in small blocks which could be useful for weights. You need to buy in quantity though

Tungsten has a much higher melting point and is a ballache to machine; if there was a cost effective alternative to mazak / zamak it would've been found by now.

[spamcan61]

1 hour ago, Joseph_Pestell said:

 

Accurascale are not using it despite bringing out their locos at very competitive prices.

Are you sure about that? I remember  one of their original announcements  mentioned Tungsten, but I'm 90% sure they backed off from that and have gone back to Mazak.

 

EDIT:- see this post 

 

Edited November 17, 2020 by spamcan61

[9402 Fredrick]

2 minutes ago, spamcan61 said:

Are you sure about that? I remember  one of their original announcements  mentioned Tungsten, but I'm 90% sure they backed off form that and have gone back to Mazak.

The competitive price was set when first announced, so they probably still have the Tungsten instead of the Mazak, but you'd have to ask them yourself to make sure.

[spamcan61]

Just now, 9402 Fredrick said:

The competitive price was set when first announced, so they probably still have the Tungsten instead of the Mazak, but you'd have to ask them yourself to make sure.

See my edit, they have gone back to Mazak / Zamak in some form.

[Hal Nail]

5 hours ago, Harlequin said:

 

 

Should the motion bracket under the footplate line up with the saddle (?) immediately above it? I always thought it was one piece extending through the running plate?

[57xx]

Yes, it should.

14 minutes ago, Hal Nail said:

Should the motion bracket under the footplate line up with the saddle (?) immediately above it? I always thought it was one piece extending through the running plate?

 

Edited November 17, 2020 by 57xx

[Harlequin]

Here’s a side view of the real thing. The motion bracket is to the front side of the saddle. So Dapol’s rendition isn’t far out.

https://www.warwickshirerailways.com/gwr/gwrls219.htm
 

[Adrock]

Video available here. I am changing the regulator slightly a couple of times - this wasn’t just on a single setting. 

 

 

 

Edited November 18, 2020 by Adrock

[spamcan61]

18 minutes ago, Harlequin said:

Here’s a side view of the real thing. The motion bracket is to the front side of the saddle. So Dapol’s rendition isn’t far out.

https://www.warwickshirerailways.com/gwr/gwrls219.htm
 

I think Dapol have it pretty much spot on, comparing with this front 3/4 view showing the motion bracket as a continuation of the plate attached to the front of the saddle.

 

https://images.app.goo.gl/Vik1QumGmBbjEeTH7

 

 

Edited November 17, 2020 by spamcan61

[Hal Nail]

1 hour ago, spamcan61 said:

I think Dapol have it pretty much spot on, comparing with this front 3/4 view showing the motion bracket as a continuation of the plate attached to the front of the saddle.

 

https://images.app.goo.gl/Vik1QumGmBbjEeTH7

 

 

Yep, thats very clear thanks. I'm more familiar with the original thinner type which more obviously lines up.

[melmerby]

I'm a little surprised that the actual slide that the con rod & piston rod connects to has no detail and is just flat sided.

[No Decorum]

On 16/11/2020 at 12:28, Karl said:

Good morning everyone, 

 

Like people have said this is a very impressive model and I'm very optimistic about the manor! Mine has a slight soft spot that I'm hoping will free up with use but there is one minor issue I'd like some help with.

 

The middle tender wheelset isn't rotating when the model runs, it turns as freely as the other two when turned by hand. Has anyone got a simple solution for this? I was wondering about a tiny bit of oil but not sure which to use to not affect the plastic.

 

4 hours ago, Adrock said:

Video available here. I am changing the regulator slightly a couple of times - this wasn’t just on a single setting. 

 

 

Thank you. That’s a useful video and seems to show the hesitation Sam’s Trains found. The centre tender wheelset can be seen to stick as Karl observed.

[Adrock]

It looks like it won’t be too long until the spares are loaded onto the DCC website. At least then we will get an idea of what is available and the price.