Fatal Break? :(

[Narrow Minded]

she was at 50psi max during this evening's trials.

That's still 25% above the DS recommendation

[dougrail]

You keep mentioning these "recommendations" but I have scoured the relevant websites and cannot find such?

[Narrow Minded]

I'm not referring to any written material, or saying that this is the case - but if they're designed to be used with the DS boiler then maybe they shouldn't be used at a higher pressure?

PS; remember the tail-end of the Mamodology conversation we had at Old Oscott???

[dougrail]

As I say NM, I do wonder if it's the case. It's a point to be thought on, afterall on the two Sunday steamings she's ran at 40-45psi. My plan was for normal running to be at 40-45 psi, and the the 45-55 psi to be used as a "turbo button" feature o the Swordbreaker.

DS have kindly got back to me already and wish to rebuild the cylinder!! I have asked if they can pressure test the cylinder to 60psi as a thought.


As for Old Oscott, do you mean the bit where I gave you the Sam Vimes look and replied "Not...my engine"?

[Narrow Minded]

do you mean the bit where I gave you the Sam Vimes look and replied "Not...my engine"?

Nah The part where I mentioned reliability issues compared to "more expensive" engines

[dougrail]

Ah yes. That was the reasoning behind buying the 'top range parts'....this was sort of expected though.

[Narrow Minded]

... Loctite 601 job

Loctite 603 copes with oily surfaces better, dries quicker and is stronger.

Having just done my "homework" I'd agree with Tony, especially if you don't already have a bottle of 601 - buy 603!

[dougrail]

DS have kindly responded again..

1)They will rebuild the cylinder.

2)They will test it for force upto 80psi!

3)Their boilers are approved for 40psi normally, but are hydrostatically tested for upto 100psi

[DolwyddelanLightRail]

Well, I can safely say Britomart can now join the club of the above picture

[dougrail]

Oh you are s***ting me James  :shock:

What happened??

[DolwyddelanLightRail]

Well, me being me, I've recently tuned Britomart up, and it's running like wonders, and I ran it outside LE as i have no stock here yet, and it was going up and down, and making so much steam that I had to stop putting water into the boiler as it was priming.

So, to get rid of some water, I decided "oh, lets drag edrig again" so I hooked it up to a dead edrig, put it in gear, and then let it go. It dragged the dead loco for about 6 yards very easily, until I heard a little "pop". I thought the steam pipe had come lose, then saw that the piston end had come out

I've currently packed it up and I'm going back to sheffield with it where I have some temperature resistant (supposedly) araldite, which I'll fix it tonight!

[-steves-]

Rather than gluing these things like people seem to do, which, what about a small "blob" of solder, which could easily be heated up and removed if needed down the line, so to speak?

just a thought?

I have had a few of these do this now, and thats what we have done to them all, no ill effects found to date.

[DolwyddelanLightRail]

Well, I would do that, if I had a soldering iron and if I could actually solder

[DolwyddelanLightRail]

and just a little picture on my desk waiting attention, sometime, when I can be bothered in between assignment writing

[dougrail]

Aww. Poor Britomart.

...what the hell is with all the rust on the wheels?!

[DolwyddelanLightRail]

Aww. Poor Britomart.

...what the hell is with all the rust on the wheels?!

Hopefully she'll live, before the weekend!

and it's great isn't it! actually the photo has shown the rust up much more noticably than it is in real life, when you look at them they just look like small bits or dirt or oil, until you look that closely up

[dougrail]

I advise you place the wheels into some deruster treatment mate Do keep us updated as to how repairs come along...

[DolwyddelanLightRail]

De-ruster? since when has my railway ever kept loco's in pristine condition? They'll go black eventually, when I can be bothered with them

[DLRdan]

Physics time !!!

A Mamod running at standard pressure of 14 PSI exerts a force of 6.91 x 10^-5 KGm^2 onto the piston and hence the end cap, in accordance with Newton's third law. At 40 PSI the force is 1.97x10^-4 KGm^2, nearly three times the force of the standard loco. The Dream steam cylinders still use a friction fit for the front and back end caps which have to with stand a huge amount of force on each stroke. The front cap has to resist more pressure, the force being the same but the surface area is smaller due to the piston rod, which is why the front end is usualy blown off. A loco running at 40 PSI has to resist the equivelent of a light hammer blow to each cylinder end cap on every power stroke. In short, stop trying to tow your Edrig and you will be fine. For those that do run with boilers at high pressures, as long as you do not just "dump" the steam into the cylinders but actually regulate the flow no harm will come to your pistons.

[DolwyddelanLightRail]

Physics time !!!

In short, stop trying to tow your Edrig and you will be fine.

well, seeing that this is the third time I've done it, and every time something has gone wrong, so this time I've learnt


First time: Wheels came loose on the axle

Second time: Steam pipe came loose and was a dear to put back in place

Third time: The picture above


I think I've learnt my lesson, for now but it's interesting what you said dan!