No engineer am I!

So, what am I doing here you may well ask. No workshop but dad did take an interest and I learnt a bit from watching him. I've inherited some tools including a pillar drill, which has proved very useful.

18 years ago I signed up to buy a 5" gauge Britannia from Modelworks. Sold as a "bolt-together kit, its turned out to be more like an attempt to bolt together, fail, modify then bolt together.

In 2017, the frames were sent away to a professional to have the motion sorted out, I could not get a smooth running loco. After a year it came back working on air and with a bag of scrap metal - some original parts had to be remade, so a good move on my part!

After much work since then, it is now steaming and running on a rolling road. The blower seems to work with one injector, the smaller injector I fear suffers from the water feed passing too close to the firebox, the water is too hot for it to "pickup"??

Once the above is fixed I will fit the finishing touches, cab, running boards etc.

The advice I need now is regarding how to take the weight off the wheels for maintenance or to sort any derailment on the club track. Each 7mm diameter bar would slide into brackets, one under the smokebox and the other the footplate.They are 6mm thick and 100mm apart, the bar would be unsupported in the middle. The bar has to be 400mm long to clear the frames and give handlers enough to hold, so a lot of leverage at the lifting points, the loco, according to Modelworks, weighs 77Kg.

What metal should I use? Strong but not brittle would be my guess. I’ve tested silver steel but that just bent!

I’ve tried local engineering companies for help, they either refuse to give advice (“not qualified to do so&rdquo or ignore my requests altogether.

Is there anyone that can give advice on what to use please?

Inverted T section, I would suggest?

Welcome, John

I don’t do Locos, but 7mm diameter seems awfully small

Could you please post a photo so that we, the uninitiated, can see exactly what you are trying to do.

… You will probably need to look here: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=103028&p=1

MichaelG.

John,

100 out of 100 for perseverance with a Modelworks kit, especially the Brit, lad in our club had one and I never saw it actually make a full lap of the track! I had a Winson traction engine (fore runner of model works) that three before me had tried to complete and failed and like you by the time I had it running I also had a box of original useless parts that had been replaced with new!

On your question trying to use 7mm bar I am afraid you are pushing the laws of physics and the properties of metals, it’s not going to happen and especially not safely. I would respectfully suggest you abandon that plan and look at an alternative of a decent bit of heavy bar perhaps with locators to stop sideways movement that you can thread through between / behind drivers that will bear directly on the frames. Having once seen two fellows trying to lift a 5” tender engine that was in steam from a bench onto a track and them dropping it with the consequential damage I would suggest any lifting operation for re railing that cannot be completed by lifting gently on the front buffers needs careful consideration and if the track where you run causes such frequent derailments that you need to make these preparations then the PWay dept have been neglecting their duty

Paul.

Another non locomotive man, but a Britannis, in 5" gauge, is not a light model., so 7 mm bar as a transverse support would seem to be too weak Better to err on the side of safety and over engineer things for your locomotive stand.

For maintenance many owners have a stand to which the loco can be fixed, so that the portion of the stand "fixed" to the loco can be rotated to invert it .

Being of the "Brick mausoleum" school of engineering, I would think of a section of at least 12mm, preferably more. The greater the distance between the ends, the deeper the section needs to be.. Considering that the total length of each transverse beam is likely to be 2-300 mm long, 38 mm angle iron comes to mind!

An increase of section depth by 50% will increase stiffness by just more than three rimes.

You are going to impose a load of about 25 Kg on the fitting at each end of the loco., so it needs to be strong enough to support SAFELY (For you as well as the loco! )

As already suggested it could be T section, to give horizontal as well as vertical stiffness.. If the loco is going to be moved out of the normal horizontal plane, it must be secured against lateral or vertical movement.

HTH

Howard

Maybe a scale forklift would be a next project?!

I had not thought about the weight of a MODEL loco until I had one ! I can JUST lift it ! As a tank loco the buffer beams are an ideal place to lift or support but a tender engine the rear end may not be so easy. For on the bench work it sits on it's rolling road,a lenght of heavy channel I had with 6 flanged ball races on each side to carry the wheels. The spacing is adjustable so ?-6-? or other wheel plan will fit up to 6 driving/coupled wheels. Easy to make.A derailment of a loco of that weight will require two men to rerail it. The cylinder drains can be very vunerable. where abouts are you in the UK. Good Luck Noel.

Many, many thanks for your responses and suggestions.

Okay, message received, the brackets are not for lifting the loco, tempting as they may look. I’ll move on to your plan B’s.

I’m not suggesting the track at the club needs attention! It’s more a lack of confidence in the Modelworks suspension. This weekend I modified my approach track and to my surprise, the loco now rolls onto the rolling road without me having to take some weight off the wheels. I was then able to watch how the suspension “moved” (or in my case didn’t move) as I pushed the loco and I’m now wondering if the suspension is too stiff. I need to take it to the club “as is” and ask… Modelworks gave no instructions on how many spring leaves to use (no, I didn’t use them all!!).

John - from Bedfordshire

John,

Getting the sprinting right on a loco is a complex affair! On a full size engine the weight carried by each wheel would be weighed (scales set in track and loco traversed over them). For a model, if the axle boxes are set down hard on the horn keeps by the springs, they are too stiff. The ideal is when the loco sits on the track the axle boxes are just floating in the horns (ie not jammed hard against the keeps). Ideally if you get a depression in the track the wheel should be able to follow it. Easy way to check if you are in the ball park is to put your hand on the boiler and rock the engine side to side (gently) you should get some movement without any of the wheels lifting clear of the track. Similarly pushing down on the front buffer beam or the cab footplate you should be able to get a little movement again without any wheels leaving the track. That would be a good rough starting point. Your situation is further complicated by the leading bogie and trailing truck. Not sure if the MW Brit has side control springs on the leading bogie? That can be in influence on the bogie following a curve or crossing a point. Springing is a really complex subject! Good luck! Be interested to hear how you get on.

best regards,

Paul.