North Sunderland stock

[Daddyman]

No one has suggested 4 individual sprung axleboxes - appears to be enough space either side of the horn guides.

You plot it, I'll build it.

I've just noticed you appear to be short of a cylinder rear David - can't have the smokebox hanging in mid-air. The other essential is the motion plate but I suspect you have enough of this to suggest the rest.

Dave! The very idea! It's part of a separate unit:

20240127_175204.jpg

The motion-support bracket is well aft of the tank fronts so invisible.

[Will L]

No one has suggested 4 individual sprung axleboxes - appears to be enough space either side of the horn guides.

Doesn't adding a fourth fulcrum point amounts to the same thing?

[davebradwell]

Sorry David, I should have had more faith. There's not much of a gap between tank and smokebox to see this stuff but it wouldn't be a steam engine without a cylinder block.

As for the separate springs, this is my usual approach but in this case it seemed a long route out of a straightforward design problem. The only way to get an advantage, as Will hasn't pointed out, would be to introduce adjusting screws on all springs and then it's getting to be more work than the simple fudge required. Fine if it's your starting point of course but bending the wire in a slightly different way only changes the spring rate - it's still just a spring.

DaveB

[Daddyman]

Sorry David, I should have had more faith. There's not much of a gap between tank and smokebox to see this stuff but it wouldn't be a steam engine without a cylinder block.

As for the separate springs, this is my usual approach but in this case it seemed a long route out of a straightforward design problem. The only way to get an advantage, as Will hasn't pointed out, would be to introduce adjusting screws on all springs and then it's getting to be more work than the simple fudge required. Fine if it's your starting point of course but bending the wire in a slightly different way only changes the spring rate - it's still just a spring.

DaveB

It also has a cylinder front (equally important, and often left off), and drain cocks. I think there should be something in the holes in the centre of the circular cylinder covers, but I can't make out what it is from the GA. Any thoughts? They almost look like globe lubricators.

20240128_110341.jpg

For me, the advantage of CSBs is that it all comes plotted courtesy of High Level and Will's spreadsheet. If there were similar resources for leaf springs I'd fit them - though from what's been said, the main advantage over CSBs is haulage, which isn't really an issue with this loco (or anything I'll ever build).

[Will L]

... from what's been said, the main advantage over CSBs is haulage....

Pardon, where's that come from. Best haulage will come from a from a chassis with the maximum practical percentage of the loco weight evenly (as equally as possible) distributed as possible. Any properly balanced sprung chassis ought to deliver that, CSB or individual springs. CSB are like that by design, while an individually sprung chassis can need a careful adjustment process

...as Will hasn't pointed out, would be to introduce adjusting screws on all springs and then it's getting to be more work ...

P.S. Sorry for the selective quote but I just couldn't resist.

And while were here, the "fitting the 4th fulcrum point" approach would have had the effect of keeping the spring wire strait so avoiding any uncertainty about the spring rate of slightly curved individual springs.

[davebradwell]

Re your cylinder front lubricators, on NER locos and many others, a section of the platform under the smokebox door could be lifted - you could see the hinges and a knob - so this would provide access.

Talking of covers, not many railways had separate rear covers and cylinders were usually bored blind from the front. The LMS did have rear covers so presumably the GW but my knowledge runs out there. They're quite easy to spot, particularly on a GA.

I suspect we've thrashed the suspension issue to death, at least for an 0-4-0. Yes, the reason for using csbs is that Will has worked it all out and it's all contained and predictable. Separate springs can be put anywhere, even where the prototype has them, so there's an infinite number of solutions and you just have to follow your instincts and preferences. Not an easy subject for a reference manual. All springs are equal in that deflection is proportional to load but small changes to wire diameter or span make a huge difference.

DaveB

[Daddyman]

Re your cylinder front lubricators, on NER locos and many others, a section of the platform under the smokebox door could be lifted - you could see the hinges and a knob - so this would provide access.

Yes, you're right of course - I'd forgotten about the hatch and the knob, even after modelling them.

The front of the cylinders seem to have the circular covers I've modelled; and I assume those are drain cocks?

Screenshot (145).jpg

This is a blurry shot from google of the rear - there seem to be circular covers?

Screenshot (2921).jpg

No luck getting it wired up today. I've got the pickups on but it's shorting somewhere, which I've never had on a model before. Can't be bothered trying to sort it tonight.

[Winander]

Are you modelling the pallet?

[Daddyman]

Are you modelling the pallet?

No, it gets in the way of the tanks...

[davebradwell]

I avoided commenting on the back end of your cylinders, David, as that would be beyond pedantic - I haven't even looked at the GA. It's impressive that you've made the effort beyond just the slidebars. Those with no cylinders should take note - at the very least they make a useful frame spacer.

DaveB

[Daddyman]

I avoided commenting on the back end of your cylinders, David, as that would be beyond pedantic - I haven't even looked at the GA. It's impressive that you've made the effort beyond just the slidebars. Those with no cylinders should take note - at the very least they make a useful frame spacer.

DaveB

Seem to remember you dared me, Dave.