Dave Holt

Mike,

I fondly remember a school visit to Oldham Gas Works at Higginshaw (and Chadderton power station). Much bigger than the one in the photo but no doubt the same fascinating equipment and intriguing aromas of tar and napher. I loved it.

Can't imagine a hoard of kids from junior school being taken round sites like that, even if they still existed, nowadays, with all the H&S concerns.

I am looking forward to further updates on your layout, in due course.

Dave.

Mike,

A very interesting looking industrial site behind the DMU in the first photo. Will that appear on your layout?

Dave.

LONDON ROAD MODELS LNER G5(S)

 

So, at the end of ten weeks, a quick photo to review progress to date on this G5 project. Still quite a bit of detailing to do on build #1 - including all of the push and pull control paraphenalia - and even more detaiing to do on build #2. Even so, build #3 will commence next Monday, when the footplate is 'laid down' - 'laid down'; sounds like building ships!!

 

Both looking very good, Mike. So #3 will have the weird tank extensions I take it?

Dave.

Surely, using a solid tube to help roll right to the edges of the boiler only works if the boiler is inside the the tube, so that the top roller has something to press the edge of the boiler against? Having the tube on the inside, as shown is no different to using rolls with a bigger top roller and doesn't alter the edge bending problem. This is also an issue in the engineering industry with pyramid rolls. Their solution is to pre-bend the plate edges in a press or use self edge bending rolls which have the rollers arranged in a different configuration, if I remember correctly.

Dave.

A wonderful little building, John. I must say I was a bit overwhelmed by your cutting notes in the previous posting. However, it has resulted in a nice ground frame cabin.

Dave.

I have two locos with pick up on the two compensated coupled axles only. One is a 2-4-0 which has the tender weighted onto the drawbar, the other a 4-4-2T with the great majority of the weight on the coupled axles. The pickups are PB strip, with small brass rubbing pads (fret offcuts) soldered at the ends rubbing against the back of the steel tyres. Both run well under exhibition conditions so the wheels and track are well cleaned but I wonder if plenty of weight on the coupled axles is a also major factor. Perhaps that is less easy to achieve with 0-4-4s.

Perhaps we can get satisfactory running with such a pick-up arrangement because of the compensated suspension keeping all four drivers in contact with the rails? A rigid chassis would probably suffer from poor pick-up without some sort of power collection on the bogie.

Dave.

Mike,

Perhaps not the lamp, but you will still require the carrying handle on top of the boiler.

My method for bogies with outside compensation beams is to attach a brass tube with 0.8 mm bore to one side, which passes right across the bogie frames and runs in vertical slots. The open end of the tube is tapped 14BA to the full length of my taps. The other side beam has a 14BA screw attached, On assembly, the two compensating beams are screwed together but leaving enough slack to allow twist relative to each other and the whole assembly to slide up and down in the slots. The cross tube then bears on the bottom of a rod inside the hollow bogie pivot tube. The top end of the rod bears on the central compensating beam of the main chassis.

Obviously, in a 4-4-0. the complication of the slots and hollow pivot would not be required and the cross tube would just run in holes.

Dave.

I believe that the full sized railway specifies a minimum tip opening of 4,5" (2.63 mm in 7 mm scale). If I'm right, presumably this should be the target dimension?

Dave.

No way cheating!! .  I superglue for various castings e.g. domes, safety valves and chimneys without any problems , just make sure it fits before gluing !!.

 

 

I have never understood the thinking/reason, that everything on a kit must be soldered, no matter what . 

Well said, that man.

Hi Mike.

Yes, I think looks much better. From the side-on photo of 67253, the full sized lever was quite hefty, but not quite as much as your original. Hope I didn't cause too much extra work but I find on my own models, once one spots something that doesn't look quite right, it just eats away and becomes the most eye catching feature on the whole model, even when it's quite an insignificant bit.

A sagging footplate might be prototypical. but probable wouldn't look right on a model and would be sure to attract adverse comments.

Great modelling and an inspiration, as always. Pity you don't turn your attentions to ex-LMS and BR Standard prototypes!

Dave.

PS. Posting at 6.22 on a Sunday morning. Don't you ever sleep?

Mike,

The G5 builds are coming along nicely and looking good. That said, I can't help thinking that the brake crank looks rather too chunky and prominent.

Dave.

Peter, There's a photo of 6230 in as-built condition on page 74 of the Wild Swan profile book which clearly shows a heat shield fitted, if that helps. There's no reason to suppose this loco was special in that respect.

Dave.

All looking very nice, Mike. I'm interested in your inset rear frame idea as I have a similar issue with a planned C13 4-4-2 tank which had joggled frames, without wheel cut-outs, both front and rear. I this case, the joggled front frames also tapered in towards their outer ends. I have calculated the wheel side throw on a minimum radius curve to establish the amount of narrowing required - just hope my trigonometry skills were up to it!

I particularly like the jumble of hoses, jumper cables and the like on the bunker and rear buffer beam on the push-pull fitted G5, 67282, shown higher up the page. Perhaps the low level camera position helps emphasise these fittings, but to me it makes the rear end so much more interesting. I gather one of your models will be so equipped?

Regards,

Dave. 

Mike,

You mention getting the body CoG in front of the rear driving/coupled axle. What suspension arrangement are you using? If it is twin beams on the coupled axles and a fixed point at the bogie centre, then a CoG roughly at the rear coupled axle will give a total weight on the bogie about equal to each of the two coupled axle (depending on the wheelbase and ignoring the axle hung motor/gearbox). It's also a good location in a triangular support arrangement for stability (a third up from the base).

Dave.

Hi Jol.

Thanks for that. A colleague of mine on P&O group models Midland in fine-scale OO, so has lots of 4-4-0's and 0-4-4's which he fits with compensation. His arrangement is to have a solidly mounted bogie (in the vertical, that is) and twin beams for the coupled axles - giving the classic three point suspension. The bogie is compensated within itself. A rather neat arrangement in my view. On the 4-4-0's, he also has the tender resting on a bar at the rear to increase adhesive weight.

Dave.

Jol,

That looks a very nice collection of models but I don't envy you the painting and lining which, again, looks very good.

Sorry to back track, but what suspension arrangements have you got on the Jubilee? You mention a sprung bogie and the chassis appears to have a fixed, driven, rear axle. So how is the front driving axle arranged?

Dave.

Pete,

I think the cab roof colour depends on the era you're modelling, in theory, at least.

In LMS days, the inside of the cab roof was painted white. However, in service it rapidly became discoloured, becoming cream and probably ending up a dirty brown or nearly black with grime.

Officially, in BR days the cab roof was black but I wouldn't be surprised if some works continued with pre-BR practice as an unofficial variation. Interestingly, BR specified black between the frames but I believe many locos were painted vermilion, as per pre-nationalisation practice.

Sorry if that confuses the issue!

Dave.

There are GA diagrams and critical dimensions in both Brian Haresnaps "Ivatt and Riddles locomotives" and the RTCS vol3 which covers the standard tank engine classes.

Both will need rescaling. The Haresnap drawing is slightly larger and clearer, but the RTCS one has more detail and has a head on view.

Both books have excellent photos of everything bar the cab interior!

The drawings in these books are weight diagrams rather than GA drawings. Being diagrams, they are not necessarily accurate or to scale. Better than nothing, but you need to be wary.

Dave.

Hi Dave,

Yes that's correct. Two beams either side at the back and a centre one for the front. Not my cup of tea really, but simple to do so I'll go with it.

 

The options for the loco are the same, or rigid rear axle and two beams either side for middle and front. Of the two I would go with the latter, but I may go for my usual simple method of fixed front and rear and sprung middle. We'll see.

Cheers,

Peter

Peter,

It's your model, but I would definitely go with the single front and twin rear beams. None of the other arrangements give proper compensation. On the other hand, perhaps 7 mm doesn't need working suspension because of its mass? Although it would give better electrical contact with the track.

Dave.

Peter,

It looks like the chassis is designed to be compensated (hole for two cross shafts). Is it one single beam and a twin beam arrangement, to give three point suspension?

Dave.

John,

Looks a very neat and tidy model. The twisted wire "chains" look very effective. If you hadn't highlighted the minor discrepancies, I doubt anyone would have noticed.

Dave.

Peter,

It looks like you could extend your idea on the Cartazzi carrier by adding the uprights from the third (narrow) alternative to the outside of your structure, in place of some of the spacing washers, if you want even greater bearing area.

I must say, your opening out of the axle slot in the tender frame looks much neater than I would probably achieve.

Dave.

Mick,

They look very neat indeed. Are the hinges stiff enough for the discs to stay where you put them in the open position. I believe the real things had clips to hold them which would be too small and fiddly to model.

Dave.

Peter,

A superb looking model and very well finished. I'm particularly taken with your technique for the lining on the bunker - a neat way round a tricky configuration. I'm really looking forward to seeing it weathered.

Good luck with the Finney A3.

Dave.

Dave,

What ever you  spot that is  wrong on my MN, it's  way too late  for my to correct, although I could  invest in the  Finney 7 overlays to improve the wheels.

 

Cheers,

Peter

Peter, it looks very good to me.

You wouldn't believe how awkward those delivery pipes are under the running plate as they wiggle past the valve gear support bracket and other obstructions, with umpteen almost inaccessible union joints - an absolute nightmare to assemble and make steam tight!

Dave.