Bow Works: Locomotives for the North London Railway

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Bow Works: Locomotives for the North London Railway

Postby garethashenden » Sun Sep 25, 2016 7:06 pm

I don't know why I didn't start this thread earlier, but I didn't. The North London Railway has three principle types of locomotives. There are two 4-4-0T passenger engines, one with inside cylinders and one with outside cylinders, both designed by Adams. The best known class is the 0-6-0T goods tanks, credit for which is usually given to Mr. Parks, although I believe they were a collaboration between him and Adams. There is also the very adorable Crane Tank, originally built as a 0-4-0ST and converted into a 0-4-2ST with a crane on the back in the 1870s. It's also notable as the oldest locomotive taken into BR stock at nationalisation.

In 4mm there are a couple of options for the Goods tank. The GEM whitemetal kit is the only currently produced version, but the Blacksmith etched brass kit can sometimes be found secondhand. Branchlines offer an etched nickel silver chassis for the GEM kit and will supply everything as a complete kit, including a detailing pack, motor, gearbox, and wheels. One of these followed me home following last year's Scaleforum. As for the 4-4-0Ts things are a bit more difficult. The compound curves of the smokebox on the 1-10 class outside cylinder engines has apparently defeated all kitmakers who attempt it. There are rumours, but not kits. The inside cylinder class 51s are a bit better off in that there is at least a kit. Well, there's a sheet of etches drawn by Peter K and available from Kemilay, if you're willing to pay now and get them when they have enough orders to fill the sheet. Luckily for me a fellow club member was selling a pair of these etches, so I snatched them up.

So there's the state of play, three kits to be built into their early 20th century condition, painted black with yellow and red lining.
One of the 4-4-0Ts was started first, eventually to be number 109. This is the number assigned to the first in the class, 51, after it was moved to the duplicate list in 1885. Originally built in 1865, rebuilt in 1886 with a cab and withdrawn in 1925. I started this in EM, as that is what I was working to at the time. The body and chassis went together pretty well, aside from the bogie which needs considerable reengineering. At some point in the process, around the time I was realising that the bogie needed more work, I came to the conclusion that it would be better for the securing bolt to go up rather than down. In other words, I had put a bolt through the footplate inside the smokebox and soldered it in place thinking that I could hold the bogie in place with a nut or two and shorten the bolt as needed. After reaching that conclusion and thinking about it for a few days I did that thing we sometimes have to do and reduced the locomotive to its component parts. It has remained pretty much untouched since then (January), awaiting P4 wheels and renewed enthusiasm. The wheels are a problem though. They should be 5'11" 16 spoke pin-between-spoke, the closest that are available are 5'8" 16 spoke, unless I want to go with 6'0" 18 spoke. I'm undecided on which option is best, which makes it somewhat easier to put off ordering the wheels. I do quite like this class though, and I'd like to get the kit reassembled, so thoughts/suggestions would be welcome.
Here is 109 on Empire Mills before its disassembly.
Image
And here is the offending bogie
Image
The recent article in Scalefour News about building a Brighton Atlantic has given me some thoughts on it, so there may be progress soon.
Last edited by garethashenden on Sun Sep 24, 2017 7:34 pm, edited 3 times in total.

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Sun Sep 25, 2016 7:40 pm

The other current project is one of Park's 0-6-0T Goods Tanks. I haven't yet settled on a number, but it will have H-spoke wheels and probably not have vacuum brakes. 78 (the second 78) and 111 are candidates at the moment.
The Branchlines chassis went together quite well. I went the CSB route first drilling holes for handrail knob fucrums. I used a home made jig consisting of three correctly spaced holes drilled into a piece of plywood with a drill press. I put the London Road models axle alignment jigs into the holes and, one axle at a time, replaced the rigid bearings with High Level hornblocks. I also used this jig to assemble the two frames with their spacers.
Here is one frame on the jig with the other next to it, ready to assemble.
Image
And the assembled frames with the cast footplate on top.
Image

I decided against the Branchlines gearbox, I'm not really sure why. I'm sure it's good, but I went with a High Level RoadRunner+ in 54:1 instead. I did use the supplied flywheel and I do notice its effect. I'm not sure I will still notice it once the other wheels are connected, we shall have to wait and see.
Image
The only problem I have with the chassis is that the guard irons are too long. They can either be at 90 degrees to the frames, which is wrong, or resting on the rails, which is also wrong. They will be shortened in due course.

Recently I have been working more on the body. Mostly I have been dry fitting parts and cleaning up the castings. I have run into a problem however with the tank top casting. This is one piece for both tank tops and the top of the boiler. Comparing it to the prototype, it looks as if the boiler doesn't curve high enough.
Compare the model:
Image
With the prototype:
Image

Various solutions involving brass tube are being considered. In the meantime I decided I was unhappy with the pockmarked appearance of the tank sides and have fretted out a pair from nickel silver. These have been joined by a new tank front as the casting for that keeps bending in the middle. I will also make a new front and back for the cab out of nickel silver, as the castings are far too thick for what was only ever sheet metal.
The two sides, still tacked together, and the tank fronts.
Image
I have a feeling that the footplate may not stay whitemetal for long...
Last edited by garethashenden on Sun Sep 24, 2017 7:51 pm, edited 2 times in total.

David Knight
Posts: 812
Joined: Sun Jul 20, 2008 6:02 pm

Re: Bow Works: Locomotives for the North London Railway

Postby David Knight » Sun Sep 25, 2016 9:05 pm

So you would classify the kit as an "aid to scratchbuilding"? ;) I think the N/S cab will look much better. :thumb

Cheers,

David

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Sun Sep 25, 2016 9:26 pm

David Knight wrote:So you would classify the kit as an "aid to scratchbuilding"? ;) I think the N/S cab will look much better. :thumb

Cheers,

David


I rather depends on whether or not you like white metal locomotive kits. I tend not to like them and that may be colouring my views on the kit. Having the kit has at least got me to the point where I feel the need to upgrade some components. If I had started out to scratchbuild the engine I don't think I would have ever actually started. I think for the next one I'll see if I can get all the little castings without the big ones, but I suspect not. In that case, the kit is worth getting for the detail castings.

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Thu Nov 17, 2016 7:20 pm

Progress has been made with the new body for the Goods Engine. I had previously cut out the tank/cab sides and tank front. Most of two months have passed in which I did some 2mm Finescale modelling, some American N scale modelling, and bought another Goods tank kit. This one however is the Mallard etched kit. The chassis is quite rudimentary but the body looks pretty straight forward and will be quite a bit faster than cutting each piece by hand. That said, given the amount I have invested in these two kits, I would like to end up with two locomotives. So I shall persevere with the scratchbuilding. To that end I have now cut out the footplate and cab back, both from 20 thou nickel silver. These five pieces have since been assembled into a box. There's not a lot of detail yet, but they already look better than their whitemetal predecessors. The next step will be chassis fixings followed by the valances and buffer beams. The valances have been cut out although they are still over length. I'm contemplating using the white metal buffer beams as they seem to be well cast and the correct size, but I may fabricate them as well. We shall see.
In the meantime, here is the current state of play.
Image
Image
Image
Last edited by garethashenden on Sun Sep 24, 2017 7:55 pm, edited 1 time in total.

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Wed Feb 08, 2017 5:24 pm

Following the struggle with the mechanism, I have now fitted better pickups. These are the coil style made from 0.25mm phosphor bronze rubbing against the flange. They were quite straight forward once I got the hang of it and I think I'll use them in future as well.

Image
Last edited by garethashenden on Sun Sep 24, 2017 7:58 pm, edited 1 time in total.

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Mon Feb 27, 2017 5:43 pm

Shortly after I made the new tank sides I made a pair of valances. These have remained stuck together until last night when they were parted and attached to the footplate. I have reached the conclusion that in order to actually get anything done on my layout I need to be able to "play trains". With that goal I need to get this engine completed enough that it can be used for shunting. At a bare minimum that is 1 bufferbeam, 1 coupling hook, and two buffer housings. I decided however to do both ends while I was at it. I'm using the kit's whitemetal bufferbeams, the thickness of the material is good here. I'm still waffling on the buffers. Both whitemetal solid buffers and brass/steel sprung buffers came with the kit. I feel that the detail is a little better on the wm ones and I'm kinda ambivalent about sprung buffers in general. I'll think it over for another day or so before fitting either. I am also expecting the postal service to deliver a new motor today. It is a Maxon coreless and should be a good addition to the mechanism.

Image
Image
Last edited by garethashenden on Sun Sep 24, 2017 8:03 pm, edited 1 time in total.

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Wed Sep 20, 2017 5:19 am

Well it's been a while, but more work has been made on the Park tank. I started by making the cab front. I fitted it to the model, then realised that none of the body pieces were square to the footplate, so everything came off the footplate before being reattached in the proper position. After that I cut a rectangular piece to form the tank tops and fitted it. The most laborious step so far was in creating the top of the boiler between the tanks. I used 3/4" brass tube, a length of which was cut slightly longer than needed. I then cut a 1/3rd or so section out of the tube lengthwise, so that I had something with the correct curvature, but too high and too long. I cleaned up the edges with a file, then set about reducing the height of the section to fit the model. I used a piece of course (80 grit) wet and dry sandpaper on a piece of glass. This resulted in a nice flat bottom for the boiler, which is what I wanted. After a bit of sanding I realised that I was still well over a millimeter away, so I trimmed most of that from one side with a piecing saw. Then I went back to sanding, checking the fit against the model as I went. Once that was done I drilled a small hole in the cab front for the safety valve handle. I think I'm going to have to replace the dome though, it's a bit big. The diameter is fine, but the flare at the base it overdone and it's too tall. But that can wait for now. The last thing I've done is I've turned a smokebox inner from the same tube as the boiler. I will make a front and back for the smokebox that will fit to this ring, then it will get wrapped to form the correct shape. The smokebox is sitting too high at the moment, held in place by blutack...

Image
Image

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Mon Oct 23, 2017 2:53 am

I never can seem to work one project through to completion. I'm always jumping around from one to another. So it's back to 4-4-0T number 109. I had disassembled most of the locomotive so that I could replace the screw in the smokebox with a nut. Well, I got it taken apart and then got distracted by some other project.

A year and a half later...

I haven't found a good way of ordering Alan Gibson wheels from the "wrong" side of the pond, so I had a friend collect a few at Scaleforum and send them on. These included P4 wheels for 109. The correct size is 5'11", 16 spoke. No one makes these, so the choices are 5'8" 16 spoke or 6'0" 18 spoke. I had gone with 5'8" 16 spoke with the EM version, because I thought that the wider flange would make up the difference and there were the right number of spokes. For the P4 version however, I have decided to go with the 6'0" 18 spoke option. I rebuilt the chassis with leftover P4 spacers from a RT Austerity kit. I then reassembled the body with the crucial nut in place. After that, I attacked the troublesome bogie. The prototype's bogie is an outside framed affair. The kit contained what I consider to be an odd way of constructing the bogie. There are two cosmetic outside frames, two functional inside frames, and a cross piece. All in all it's quite a flimsy design with virtually no bearing surface. It looked like this:
Image

What I came up with a design that is far simpler and stronger. I kept the outside frames, but got rid of the rest. I took a piece of fairly thick brass flat stock, about 1mm thick. I drilled two holes and joined them to make a slot with a piecing saw. This would let the bogie move from side to side, rather than just pivot around the mounting. I chose to use the pinpoint axles, rather than inside frames. Unfortunately, the outside frames have rectangular openings for the axleboxes, not round ones for bearings. I dug around in the spares box for a while and came up with some bearing carriers from some Bill Beford sprung w-irons. Bearings were fitted, but the hard part was lining up the bearings in the openings. The first one was easy, the other one on that side was measured 6' away and fitted. After this I stuck the sideframe to the crossmember. I added two pieces of rectangular brass tube to the ends of the crossmember to reinforce things a bit. The side with the bearings was fitted and a pair of wheels fitted. Predictably, the wheel hit the crossmember, so out came the piercing saw and the file. Once the wheels fit, I attached the other sideframe, making sure to keep the axles square with the sideframes. The bogie is square and doesn't rock on a glass surface, so I'm optimistic. Right now I have fitted a short length of brass tube between the bogie and the footplate to set the ride height. This isn't an ideal solution and is putting the front of the locomotive lower than it should be. I intend to fit both vertical and lateral springs, probably just lengths of phosphor bronze wire, to control the movement of the bogie, hopefully these can help regulate the height as well.

Here is the underside of the bogie, hopefully it all makes sense.
Image

And the rest of the model:
Image
Image
Image
Image

And with the Goods Tank
Image

Lots more to do. Bogie springs are probably first, then the cab interior.

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Sat Feb 16, 2019 3:17 pm

At the beginning of January I bought a 3D printer and have been printing all sorts of things since then, mostly in N scale. I’ve had trouble making the short section of exposed boiler on the Goods Tank, it’s either the right length or the right diameter, and never round enough, so I thought I’d try printing it. The design is quite straight forward and it’s far more repeatable than my attempts to roll metal. The only thing I’m not satisfied with is the chimney. The flare to the sides of the smokebox isn’t big enough and it’s not as well defined as I’d like. I’ll try to fix it, but I may end up using the cast kit chimney.

Image

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Mon Jan 31, 2022 12:32 am

With the Broad gauge Buffalo essentially finished, aside from paint, its time to find a new project. The paint will have to wait for warmer weather. After about five years of procrastination I decided it was time to tackle the outside cylinders on the Park Tank. I had initially procrastinated over the lack of clearance between the piston and the front crankpin. I replaced the front crankpin bush with a little bit of brass tube, and turned the crank pin nut around so that it would sit as flush as possible. But this wasn't enough. The kit comes with two cylinder options, an OO/EM one and a P4 one. The P4 ones are shorter, so that the overall width stays correct. In theory. In practice I decided to use the OO cylinders and even with them there is barely clearance between the rods and the piston.

Image
Image

I have also decided against the printed boiler and smokebox and set about making them from 0.020" nickel silver. The front and back were sweated together and fretted out. Then I cut a strip of nickel silver the width of the smokebox minus the front and back. When cut to the correct width it was attached to one of the ends. Then a vertical piece was attached, then the other end.

Image

I cut a strip of 0.010" brass the width of the smokebox, plus a little just for safety. This has been rolled to shape and will be trimmed to length once it has been attached to the smokebox.

Image

davebradwell
Posts: 1174
Joined: Fri Jan 18, 2019 3:48 pm

Re: Bow Works: Locomotives for the North London Railway

Postby davebradwell » Mon Jan 31, 2022 9:36 am

It's easy to see why you've had trouble at the front crankpin as the design of the kit is such that the conn rod isn't in-line with the piston rod and is fixed to the inside of the crosshead rather than being contained within it. This has lost you well over a mm each side. It's also necessary to file face of driving wheels flush with face of tyre with outside cylinder engines (except GW and some Southern). There also appears to be a boss on outside of front conn rod bearing. Have a look at a proper GA drg of almost anything to see what I mean. Kit would seem to be designed by a 00 modeller. I hope your widened cylinders don't foul platforms.

Have you spotted cylinder going up-hill in side view? Cylinders should point at centre of wheel they're driving.

DaveB

User avatar
Winander
Posts: 847
Joined: Thu Mar 20, 2014 12:19 pm

Re: Bow Works: Locomotives for the North London Railway

Postby Winander » Mon Jan 31, 2022 10:55 am

davebradwell wrote:It's easy to see why you've had trouble at the front crankpin as the design of the kit is such that the conn rod isn't in-line with the piston rod and is fixed to the inside of the crosshead rather than being contained within it. This has lost you well over a mm each side. It's also necessary to file face of driving wheels flush with face of tyre with outside cylinder engines (except GW and some Southern). There also appears to be a boss on outside of front conn rod bearing. Have a look at a proper GA drg of almost anything to see what I mean. Kit would seem to be designed by a 00 modeller. I hope your widened cylinders don't foul platforms.

Have you spotted cylinder going up-hill in side view? Cylinders should point at centre of wheel they're driving.

DaveB


Dave,
To progress my education in respect of these matters, the wheels in the top picture appear to have spokes that slope out towards the boss - i.e. the wheel is convex. Are you suggesting that the the spokes should be attacked to make the face of the wheel flat? I don't discount the possibility that the wheel could be deformed as the middle wheel doesn't look as convex although my opinion could be a result of photographic distortion.

I was at first struggling to see why the piston was at the wrong angle until the "doh" moment when I realised that the middle axle is the driven one. Could you secure the conn rod without a head on the rivet or would it be appropriate to put the head on the outside which would make it possible to file the back nearly flush?

Thanks for your continued effort to educate us.
Richard Hodgson
Organiser Scalefour Virtual Group. Our meeting invitation is here.

davebradwell
Posts: 1174
Joined: Fri Jan 18, 2019 3:48 pm

Re: Bow Works: Locomotives for the North London Railway

Postby davebradwell » Mon Jan 31, 2022 12:22 pm

If you can find any GA anywhere - perhaps in a book - you will see that where there are outside cylinders, the wheel boss is flush with the tyre (but be wary of GW and Southern). The spokes may still taper so I can't say how Bow Works did it but the boss would not protrude. We are at a further disadvantage when trying to get clearance here that at 2mm, our wheels are slightly thicker than the usual scale 1.85. Yes, if I was building it I'd have to find room for the overlays somehow within these limitations - I don't know if spokes should be flat or not.

Correcting the design problem is not easy with the cast crossheads. You might cut a piece out of the rear (opposite end to cylinder) and fit a new front and rear from sheet to enclose the conn rod and put it in-line with the piston rod. Gudgeon pin can be made from rivet with head filed hex for appearance and retained in coutersink at rear. Riveting is safer than soldering here. There'll be other ways including some that give a more convincing slidebar as the kit is rather mean in the thickness of the motion but I'm assuming you're stuck with it all.

You could certainly have a thinner head on the back of the pivot - file it down to just a few thou' thick.

Check your slidebar is correctly aligned - put rule along top of cylinder and see if it's in-line.

Anyone have a GA for one of these?

DaveB

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Mon Jan 31, 2022 1:12 pm

I do have a GA, but it’s at home and I’m at work. I’ll post it when I get home.
I know one of the cylinder is crooked, it’s hitting the valance because it sticks out too far.

I think the best course of action would be to fabricate a new crosshead. This is the first outside cylinder locomotive I’ve built, so I put together the parts I had. Now that I see their shortcomings I can correct them. Much like replacing the white metal body pieces with nickel silver.

hughesp87
Posts: 137
Joined: Tue Aug 05, 2008 8:25 pm

Re: Bow Works: Locomotives for the North London Railway

Postby hughesp87 » Mon Jan 31, 2022 2:09 pm

Gareth / Dave,

Allow me to post the GA sections that I have.

IMG_4404.JPG


I have built the Mallard / Blacksmith version in the past and have another one on the shelf to build this year. The crosshead for that kit is a folded etched assembly that fits neatly over the slidebar and gives just about enough clearance to the rod and crankpin in P4.

Regards,

Geraint
You do not have the required permissions to view the files attached to this post.
Geraint Hughes
Cromford & High Peak in P4
Danish Railways in P87

Philip Hall
Posts: 1947
Joined: Mon Aug 10, 2009 7:49 pm

Re: Bow Works: Locomotives for the North London Railway

Postby Philip Hall » Mon Jan 31, 2022 4:03 pm

I would file something off the rear of the crosshead so as to be able to rivet the conn rod better in line with the piston centre line. I would also file off the boss on the rear of the front end of the coupling rod. OK it's not quite the done thing but you will never see the fact that the thicker end of the coupling rod is no longer there. The final option (if you should need it) is to reduce the boss on the driving wheel to bring it flush with the tyre rim, but with luck and the first two suggestions you shouldn't need to do that.

Philip

davebradwell
Posts: 1174
Joined: Fri Jan 18, 2019 3:48 pm

Re: Bow Works: Locomotives for the North London Railway

Postby davebradwell » Mon Jan 31, 2022 4:53 pm

I've discovered a little trap around here. If you go to the photos on mikemorant.smugmug.com there is a rear 3/4 view of 58859 which has the H section spokes. Apart from noticing that these look very flat on the face with a round boss around the axle, look at the conn rod on top centre and slidebar - this is grooved to give clearance. Now your wheels may not have the same stroke so there's a first check but you can see there's no half measures here - it's either a model or you sign up to get everything the right width and in it's correct position. It certainly explains the kit's thin slidebar and conn rod on the rear of crosshead.

DaveB

User avatar
grovenor-2685
Forum Team
Posts: 3918
Joined: Sun Jun 29, 2008 8:02 pm

Re: Bow Works: Locomotives for the North London Railway

Postby grovenor-2685 » Mon Jan 31, 2022 7:55 pm

Well, hard as I look at that photo I don't see any grooves in the connecting rod. The slidebar rear support is an inverted U shape to clear the con rod, is that what you mean?
Regards
Keith
Grovenor Sidings

davebradwell
Posts: 1174
Joined: Fri Jan 18, 2019 3:48 pm

Re: Bow Works: Locomotives for the North London Railway

Postby davebradwell » Mon Jan 31, 2022 8:22 pm

Yes the bracket is notched deeply but the top of the conn rod is still clearly above the bottom of the end of the slide bar and this situation without springs being depressed to limit of travel, or even beyond in the case of a model. It may be only a slight clout but it's there. The side view shows the relative heights of the components. The point I'm making is that in order to make an accurate representation, the conn rod has to be in its correct lateral position to clear the notch just in a scale bracket and not be able to deviate far from it, perhaps due to excessive sideplay in various components.

DaveB

garethashenden
Posts: 405
Joined: Tue Apr 07, 2015 9:41 pm

Re: Bow Works: Locomotives for the North London Railway

Postby garethashenden » Mon Jan 31, 2022 10:31 pm

This thread epitomizes the phrase "Better Modelling Through Peer Pressure", and I mean that in the best possible way.

Ted Scannel has sent me a number of pictures of 58850 taken at the Bluebell Railway with the aid of a tape measure. When comparing those dimensions, the GA, and the model, I've arrived at the following conclusions.

1) The wheels are the correct width. They're Gibson wheels with an etched overlay to represent the H-Spokes. For the next one of these I build I'll probably 3D print the wheel centers, but for now they're staying. They also look pretty true by eye with the exception of a small nub on the ends of the axles. This will be removed.

2) The boss on the front of the leading side rod is close to the correct width. Should be 2 3/8". (2.375)*(25.4)=60.325mm. (60.325)/(76.2)=0.791mm. The measured model is 0.91mm. The crankpin nut flange measures 0.25mm thick. I think the prototype crankpin nut looks about right and the GA looks similar. So we can loose 0.1mm from the boss.

3) The bracket at the end of the slide bar looks fairly straight forward to make. Two main notches, a big one for the side rod and a smaller one for the connecting rod. May as well take the opportunity to make the slide bar the correct way as well. It has a tapered notch at the end to give clearance to the connecting rod.

4) The crosshead is about the only thing NOT shown on the GA. I may be able to make it from the pictures I now have. If not, the NRM has the original drawing. They have lots of drawings. Part of me wants them all, but not a £27 a copy.

5) If I'm redoing the slidebar, crosshead, and piston, I may as well do the cylinder covers. The whitemetal castings didn't suffer extensively, but they're not pristine anymore either. Should be able to turn up something suitable.

6) It would be nice if the cylinder/slidebar/bracket assembly could be removed as a unit, at least while trial fitting and painting is going on. Any ideas how to do this?

User avatar
Jol Wilkinson
Posts: 1113
Joined: Mon Jul 21, 2008 7:39 pm

Re: Bow Works: Locomotives for the North London Railway

Postby Jol Wilkinson » Tue Feb 01, 2022 9:38 am

Gareth,

the Sharman wheels LNWR H spoke wheels are noticeably flatter - the wheel centre is actually recessed - compared to the AGW version. That is a standard spoked wheel with the brass overlay as you describe.

Unfortunately the Sharman version is no longer available in P4 although the PPP website still shows OO/EM versions available to order.

LRM CT 34RP2.jpg
You do not have the required permissions to view the files attached to this post.

davebradwell
Posts: 1174
Joined: Fri Jan 18, 2019 3:48 pm

Re: Bow Works: Locomotives for the North London Railway

Postby davebradwell » Tue Feb 01, 2022 9:52 am

All my locos have the cylinders made into a unit as you describe, Gareth. The slidebar bracket is made to go right across the chassis, located in slots in the frames and screwed down by a tab into a horizontal stretcher. Cylinder are a single unit, similarly screwed down. The slidebars are very securely located in the cylinders and pass through slots in both front and rear - by etching them good alignment is obtained but with a little care it should work for you. Where clearances are tight, it's useful to use something like a drill shank as a feeler to get slidebar parallel to frames. Crosshead is a close fit on slidebar but the cylinder gland is relieved for all but a short portion so it can tolerate misalignment - a little turning job here, oval flange and all. A few more sums will confirm how close to the magic 6ft 8in youcan get before you start building.

You might make a crosshead like this:

Img248.jpg


DougN has just made a couple of these for his J26. Put a bit of fag paper top and bottom of slidebar while soldering to give some clearance. They'll need piston rod from 1mm wire and a bit of tube to represent the nose - use cylinder as jig to locate. However you make them the enemy is fillets of solder in the corners of the square hole and this design makes those less likely. The top bit will be in thin material in your case as top is only a litle wider than bottom.

You need a volunteer to go to NRM and photograph the drg.


Those wishing to learn a little of steam loco construction might compare the cross section of the wheels on this outside cylinder loco with the J26/27 plan view I posted recently on DougN's thread. Here, with the demand for larger cylinders, they've pushed the axleboxes out so the backs of the wheels are dished to accommodate them, resulting in a large boss on the outside to maintain a decent thickness. This is very common on all but the earliest locos.

DaveB
You do not have the required permissions to view the files attached to this post.

DougN
Posts: 1252
Joined: Wed Sep 01, 2010 9:57 am

Re: Bow Works: Locomotives for the North London Railway

Postby DougN » Tue Feb 01, 2022 10:09 am

Thanks for all your info Dave. I have another suggestion to help with clearances.. yes the fag papers worked... i tend to use a sharpie pen to blacken things i dont want soldered together as well. Draw on the item in the pen then wrap in paper once it is dry.

It has helped me out of number of situations where i don't want things soldered together.
Doug
Still not doing enough modelling

User avatar
zebedeesknees
Posts: 330
Joined: Mon Jul 12, 2010 5:15 pm

Re: Bow Works: Locomotives for the North London Railway

Postby zebedeesknees » Tue Feb 01, 2022 10:56 am

garethashenden wrote:This thread epitomizes the phrase "Better Modelling Through Peer Pressure", and I mean that in the best possible way.

Ted Scannel has sent me a number of pictures of 58850 taken at the Bluebell Railway with the aid of a tape measure.

Ahem... for the sake of accuracy and credit where it is due, those pictures were taken and sent to me by John Brighton. I believe that the loco was at the time on loan from the Bluebell at a site more local to John in Sheffield.

Ted.
(A purists' purist)


Return to “garethashenden”

Who is online

Users browsing this forum: ClaudeBot and 0 guests