Corbs' Cobbling - Is it electric?

[Corbs]

As well as the P2, I'm also resurrecting a stalled project, that of the C7/3 streamlined atlantic.

 

The fact:

 

Raven's C7 4-4-2 locos were built between 1911 and 1918 and the class numbered 50. They were 3 cylinder locos and used on express services.

In 1931, Nos. 727 and 2171 were fitted with boosters on their rear bogies and enlarged boilers operating at 200psi instead of 175. The rear bogies were extended to two axles, and articulated the engine and tender. These two locomotives were reclassified as C9.

In 1937, Gresley considered rebuilding the C7s in a similar manner to the B16/2 4-6-0s, replacing the Walschaerts valve gear on the central cylinder with his conjugated valve gear. The proposal was expensive, and was overtaken by the rapid introduction of the V2 2-6-2s. No C7s were rebuilt with Gresley's conjugated valve gear.

(from www.LNER.info , a brilliant source)

 

An example of a Raven B16

http://s0.geograph.org.uk/geophotos/02/84/76/2847647_e3d46199.jpg

and a B16/2, showing the different valve gear arrangement

http://s0.geograph.org.uk/geophotos/02/84/83/2848333_bf00d450.jpg

 

The fiction:

A sole C7 was converted as per Gresley's proposal and designated C7/3, with Walschaerts/Gresley valve gear and the enlarged Diagram 109 boiler as used on the C9. Given the trends of the time, the loco was streamlined to imitate the class A4 and B17/5 locos. As the mixed traffic V2s proved so versatile, no further locos were converted and the C7/3 was eventually sold to the NWR (possibly as Thompson took the helm in 1941).

 

I'd already got part way through this project a few years ago, cutting and shutting a GBL 'Mallard' body, and a 'Princess' chassis with the front axle removed. I think I had changed my mind about the driven axle, now I've decided on the look imitating the B16/2, I changed the pins around so I can attach the valve gear.

 

 

The valve gear I have use for this is broken into two halves, but I've ordered one with a complete motion bracket that should make things easier.

 

On the P2/4, experimenting with valve gear and cylinders from a B1, it looks like the connecting rod is roughly 1cm too long, as the cylinder needs to roughly line up with the steam pipe.

 

Edited August 24, 2017 by Corbs

[Corbs]

Hi Corbs

 

If you look at the Hornby P2 thread, page 98, post #2450 there are 2 pictures posted by Graham King of the P2 chassis both fitted with Bachmann V2 Valve gear.

Brilliant, thank you so much!

[richard i]

 

Like the idea and the standard of modeling. Most impressed. One question though. As narrow firebox locos would the streamlining have looked different at the back end?

Edited January 7, 2017 by Andy Y

[Corbs]

Like the idea and the standard of modeling. Most impressed. One question though. As narrow firebox locos would the streamlining have looked different at the back end?

Thank you, and yes you are right it would likely have more closely resembled the streamlining on the B17/5 locos. If I were doing this properly I could have used one of the resin bodies mated to a 4-4-2 chassis, but as it's a cheapy flight of fancy, maybe I should adapt the legend to have the rebuild include a wider firebox such as that fitted to the C1 Atlantics

 

I think I had previously swapped the driving axle around as I had intended this to be a C1 rebuild, but the fact that Gresley had wanted to rebuild the C7s in the 1930s anyway seemed to fit better.

 

Also, Bachmann's customer service is really quick. They have V2 valvegear and cylinders in stock so i'm going to order some of those for the P2.

Edited January 6, 2017 by Corbs

[gr.king]

Hi Corbs

 

If you look at the Hornby P2 thread, page 98, post #2450 there are 2 pictures posted by Graham King of the P2 chassis both fitted with Bachmann V2 Valve gear.

For clarification, before anybody tries to fit Bachmann V2 valve gear to the Hornby P2 chassis and gets a surprise, those two images don't in fact show Bachmann valve gear. It might fit, albeit in a slightly "scrunched up" way, because I know that Simon Martin has managed to fit such valve gear to an interpretation of a Thompson Pacific. Those pictures however show a combination of valve gear parts from different sources, fitted to adapted Bachmann V2 cylinders. The con-rods, slidebars, crossheads and the return cranks are original Hornby P2. The drop links added to the crossheads, along with the union links and the combination levers (the front parts of the Walschaerts gear) are from a Comet V2 etch. The eccentric rods, radius rods, expansion links and the distinctive motion bracket come from an etch designed largely by Morgan Gilbert to aid conversion of Bachmann Peppercorn A2s into one of the Thompson versions. The long reversing rods are made up from nickel silver strip. Use of this mixture of parts demands a bit of work and ingenuity, but it results in valve gear that actually fits properly in the very limited space between the cylinders and the driving wheels. The motion bracket from the special etch doesn't fit directly onto the P2 chassis block, it has to be modified.

[Corbs]

Thank you for the clarification Graeme, I've dropped you a reply to your PM on the LNER forum.

 

In other news, not freelance modelling per se but something I was rather chuffed with. Found a railroad 'Duke of Gloucester on ebay, looked like it had been dropped, with scuff marks on the side, so I thought it may make a good donor for something. It was also listed as a tank engine - someone had lost the tender it seemed!

I put in an offer of £45 which was accepted, it arrived today, upon inspection the 'scuff' turned out to be a smudge of paint which rubbed off! I was over the moon, there appeared to be no real damage. I fished about in the drawer and found a GBL 9F tender, I know it's not the right one but it's a rough colour match at least. Popped some wheels on it and posed for some pics.

It runs so smoothly! Amazing.

 

Edited August 24, 2017 by Corbs

[gr.king]

Think its time I left RMweb.

 

Don't despair......

[gr.king]

My main concern about the V2 valve gear stems not from wheel size and cylinder position, but from the fact that the wheel spacing is greater on the V2 and the driving axle position therefore 3mm further back than on the P2. Somewhere, the parts of the V2 motion must be longer by a total of 3mm. It may in fact fit, without parts interfering and locking up, but the appearance may not be ideal even if it does fit. I gather from personal communication that Corbs will be having a go, so we'll all know soon enough......

 

I'm afraid I haven't tried a P2 chassis under a Gresley Pacific body so I can't advise at present on that one. It potentially offers an intriguing way to portray the original P2 concept, before all the fairings, water heater and poppet valve gear were decided upon.

[Corbs]

If it all goes to heck with the V2 valve gear then I may have to get over my morbid fear of etches and soldering and have a go at the proper conversion

 

Just for you Mr Mersey I took a pic of the P2 chassis alongside a GBL Flying Scotsman body....

 

Looks like the body may need extending?

 

On the Duke today I cut out the horrid moulded coal from the GBL tender, added some styrene and used a sponge sprayed black and coal glued to it again as per the NCB wagons.

 

The loco to tender gap was quite big (I guess because this was meant for a 9F with the huge overhang) so i cut off the steps at the front, chopped a chunk out, and re-glued.

 

Then I added a strip of styrene to close the gap to nearly footplate level, and painted the axle boxes yellow. If I'm feeling really brave, I might attempt a red stripe.

 

Looks much better now, not bad for £45 of loco, £5 of tender and £3 of wheels!

 

The A4 valve gear doesn't fit the C7 as I had wished, I'm going to see if I can give the V2 valve gear a whirl when that arrives.

 

I do want to repaint the C7 into dark blue, is there an (relatively) easy way to do the parabolic curve? It's quite daunting so I was considering carefully masking it out and leaving it as much as possible.

 

I have started the single chimney conversion, though.

Edited August 24, 2017 by Corbs

[micklner]

Fox do a transfer for the curve. Very fiddly to apply !

[richard i]

Where is the single chimney from please, or did you hack back a GBL one?

Edited January 7, 2017 by Andy Y

[Corbs]

Peter's Spares do them, it's a Hornby one from the live steam engines they made

http://www.petersspares.com/Hornby-x9301-live-steam-class-a4-single-chimney.ir

[Corbs]

A few updates...

 

The Duke now has a splash of red and yellow on the axleboxes.

 

The V2 valve gear has arrived so I can start mocking things up on the P2/4. Puny cylinders though.

 

Slightly squashed but a better fit then the B1 examples. This will enable me to work on the body extension and front of the running plate. Then, i think I need to work on securely mounting the body so I can mount the cylinders properly.

 

These GBL 9F cylinders look beefier and more like the B1 examples (actually these are Hornby ones in the pic but I will swap for GBL ones)

 

I drilled a hole and glued in some rod to take the piston shaft.

 

Think I'll need to graft the slidebars from the V2 gear onto the 9F cylinders.

Edited August 24, 2017 by Corbs

[richard i]

A few updates...

 

The Duke now has a splash of red and yellow on the axleboxes.

 

The V2 valve gear has arrived so I can start mocking things up on the P2/4. Puny cylinders though.

 

Slightly squashed but a better fit then the B1 examples. This will enable me to work on the body extension and front of the running plate. Then, i think I need to work on securely mounting the body so I can mount the cylinders properly.

 

These GBL 9F cylinders look beefier and more like the B1 examples (actually these are Hornby ones in the pic but I will swap for GBL ones)

 

I drilled a hole and glued in some rod to take the piston shaft.

 

Think I'll need to graft the slidebars from the V2 gear onto the 9F cylinders.

I think you can see the extra 3mm in the valve gear , it might benefit from shorter rods to bring them parallel . I hope you can see which rod I mean near the top and the union link(?)

Richard

[gr.king]

Put a wrapper or two on the existing cylinders?

 

That's what I did for Earl Marischal.

[Corbs]

Put a wrapper or two on the existing cylinders?

 

That's what I did for Earl Marischal.

That's a good idea, if that fails I could change the 'skin' over and keep the internals/mounts which might be more robust. I was surprised to find the slide bars were plastic.

 

Richard - you may be right there, until I get the body mounted and the running plate fashioned I don't think I'll be able to make a call on it.

(also sorry to ask but please could you avoid 'quoting' the post as it clogs up the thread with lots of duplicated images? I think its a side effect of using photobucket rather than the forum to host images)

[richard i]

ok will do, only did it to keep the comment with the image it is about.

Richard

[Corbs]

Graeme's resin parts have arrived and allowed me to mock up the model and get an idea of length.

 

There's a few different ways I could proceed with this. I guess the easiest would be to cut off the resin steam pipe, extend the original one down to running plate level, and mount the cylinders a bit lower than originally planned. I'll need to notch the back of the running plate to clear the driving wheels but this method is tempting.

 

 

The other option is to cut the resin extension up, move the 'upper' section forward so the step down is just under the smokebox chin, and let in a new section. The downside of this is having the make up the remaining section, and having multiple breaks in the running plate to mask.

For an easy life I'm swinging towards option 1 at the moment.

Edited August 24, 2017 by Corbs

[gr.king]

Between Bachmann, Hornby and me we seem by the look of it to have achieved some sort of consistency of allegedly scale dimensions, which is reassuring, given that those resin pieces were never meant to fit that model, but they ought to fit given the relationship of the A1 and A2 classes.

[Corbs]

It's a spot-on fit as far as I can see!

 

The chassis is not far off the P2 one as well at the front, although I need to remove some more material from the underside to get it snug around the chassis block.

 

 

This is the model after a hole has been cut for the body screw mount, and the 9F cylinder mocked up in position.

Edited August 24, 2017 by Corbs

[micklner]

Cylinder Top looks too high at the moment ? Getting there !!

[gr.king]

You're probably well aware of this, but don't leave that temporary blackening from the marker pen in place when you try to paint the smokebox extension - it may prevent the paint from drying.

[Corbs]

Cylinder Top looks too high at the moment ? Getting there !!

 

Yes I think it might struggle with the loading gauge currently!

 

You're probably well aware of this, but don't leave that temporary blackening from the marker pen in place when you try to paint the smokebox extension - it may prevent the paint from drying.

 

Gotcha, it's only black-tacked in for now and will need to be glued, filled, sanded etc but definitely worth bearing in mind.

[scots region]

Corbs, is something up with your photobucket account? Its just I can see any of the photos in either Chrome or Safari, could just be me though

 

Cheers

ScR 

[Corbs]

Hi Corbs.

 

I would like to apologise if my suggestion for using the V2 valve gear was incorrect.

 

Looking forward to seeing the result when she's finished.

 

It's alright, no one died

 

 

Corbs, is something up with your photobucket account? Its just I can see any of the photos in either Chrome or Safari, could just be me though

 

Cheers

ScR 

 

I think photobucket was undergoing maintenance yesterday, seems like it's back online now though.

 

Not much to report at the moment as I managed to wreck the running gear of my freelance Avonside 'Perseus' which was a frustrating ordeal. Might get back on the mainline locos tonight.