Royal Scott ash pan.

[Ian Mackay 1Participant @ianmackay1]

I am helping a friend who is unable to help to get his 5” Royal Scott back in ticket. The model is a great example but I can find no way of dropping the ash pan or grate. I have no drawings to go by and my friend has nearer steamed it since he bought it.

I am reluctant to fire it without the option of dropping the fire if required.

Can anyone help with suggestions or give an indication of where and what I should be looking for. All I can see is the damper at the front.

[Ian Mackay 1Participant @ianmackay1]

[RolsterParticipant @rolster]

Hi it may sound obvious, but i have seen transverse pins used between the second and third driving wheels to hold the grate and then by removal drop it out.

If you don't see one, use a small dentist mirror to check the grate and see if its a one piece or a multiple piece grate, two or three sections.

Some boilers have been designed with split grate so you reach in with your rake or other tool and upset the grate and pull a section out through the furnace door and this dumps the fire through the grate and out under the engine.

This keeps the model looking more scale but can be slower in an emergency when you need to drop the fire. For normal end of run type dumping or maintenace it makes no real difference.

BR Roland

[Nigel Graham 2Participant @nigelgraham2]

This has come up before.

Worry thee not!

It might have a rocking-grate of some form, but anyway your description suggests no reason the locomotive cannot be used.

.

Last year I think now, one of ME's regular contributors (Doug Hewson if I recall correctly) wrote of someone barred from running his locomotive at a club track by the club's boiler inspector because the grate could not be dropped rapidly. The author pointed out that the ban was wrong.

I studied my latest-edition copy of the MELG. It contains NO recommendation, let alone requirement, for a quick-dropping grate. It does not even mention grates! The rules are of pressure-vessel integrity not fire-grate design.

.

Another writer around the same time (Peter Seymour-Howell?) described his own fine-scale 5"g loco's grate and ash-pan as close to original, I think with a rocking grate in some form. There is too much steelwork around the chassis for dropping the whole lot out. He explained that should you ever need put the fire out rapidly, stuff rag down the chimney to block it, and turn the blower on hard, with the fire-door latched shut. It cuts the air-flow, pushes the fire gases backwards down into the ash-pan, and smothers the fire – keep hands clear lest any blow-back from below the footplate.

.

Better than a grate section made for wangling out through the fire-door and hopefully wangling back in (when the engine is cold!), is to hinge that part at its front end, released by a catch whose control lever imitates that for the full-size rocking-grate or second damper control.

.

The BR Standard full-size rocking-grate looks fairly complicated in the official Handbook diagrams (I've not seen one in the steel) but I would think a miniature edition, feasible.

It is divided cross-ways, with extensions below the bars pivoting on longitudinal links connected to a lever on the footplate. The geometry is that of a parallelogram.

The lever has a simple safety-collar to limit fire-bar movement and gaps to breaking and dropping clinker into the ash-pan without losing the lot. Raising the collar gives full travel to tip the fire-bar sets nearly vertically to drop the fire; not into the ash-pan, but through the pan's open doors into the disposal pit.

.

There is no reason that Royal Scot cannot be certified for service purely on grate and ash-pan design. It simply needs extra care in use, and knowing what to do if it ever becomes necessary to put the fire out rapidly.

I may be wrong but I think your friend's Royal Scot having a damper makes it unusual among miniature locomotives; and I've often wondered why that is. However, it also leads me to ask if it has a lever-operated grate as well – I would expect its lever to be be on the fireman's side of the footplate, perhaps next to the damper lever.

.

If the grate cannot be dropped or swung open, the only disposal method is to shovel the fire out, which is fiddly and risks a messy cab, but does not take long. May be best done after the fire has died out and locomotive cooled down naturally; the slower cooling also better for the boiler as well as your fingers.

My preferred disposal method with our club's loco, a 7.25" g 'Wren' which does have a one-piece drop-grate /ashpan assembly, is to slice a lot of the run-down fire down through the grate, shovel the rest out, then rake the ashpan empty – no dropping an assembly which on this specimen is awkward to replace.

You don't want to leave clinker in the firebox or embers jammed between the bars, but odd bits of half-burnt coal loose on the grate won't hurt. The next running session will use them up!

[duncan webster 1Participant @duncanwebster1]

If it's not sectional so you can get it out through the fire hole and you burn the grate, (not unknown) then it's a boiler off job.

[Ian Mackay 1Participant @ianmackay1]

Thanks guys.

I know it’s not a test requirement, but it does make cleaning the grate a bit fiddly. I think we can rake the ash out forward through the damper.
I will take my boroscope and have a better look in the fire box on Sunday to see if it’s a split grate.

[Author]

Posts