Roundhouse Garratt

[jabsteam]

I'd like to put together a 0-4-0+0-4-0 Garratt from Roundhouse components; 2 sets of Katie running gear underneath a Lady Anne boiler.

My question is; will the Lady Anne boiler make enough steam to run 2 sets of Katie cylinders?

[laalratty]

Probably not, the Locobox Afrakarn garratt uses two sets of R/H running gear and it has a bespoke boiler, and you wouldn't want it to be any smaller, it can be a bit marginal for steam. This boiler is a bit bigger then a Lady Anne boiler

[Keith S]

I have no scientific reason for this belief, but on a regular four-coupled roundhouse engine, if you run it at a scale-ish speed, you still have to have the burner turned way down to stop it blowing off, even with a reasonably heavy train. I wonder if the Lady Anne boiler doesn't make enough steam to run two sets of cylinders as long as you don't make it go very fast. What do I know though.. I only have 5 wagons and two coaches. My Roundhouse engine has an easy life.

I'd be tempted to give it a shot. If the boiler doesn't make enough steam then blank off the steam supply to one set of running gear. A standard Roundhouse locomotive could easily drag an extra set of running gear around behind it... you'd never even notice that one end wasn't running!

My uneducated opinion anyway. My engine can go twice as fast as one might sensibly expect... does this mean that it could run two sets of cylinders at a reasonable speed?

[laurence703]

Hmmm... I dunno... I'd agree with Laalratty on this one... if you can get your mits on a bigger boiler then you'd have more weight and more adhesion and more steam producing capacity...

see if they'll sell you a Leek and Manifold boiler?

[Keith S]

You're probably right. I just want to see someone build one. I love Garratts.

[Llanwellyn]

I'd like to put together a  0-4-0+0-4-0  Garratt from Roundhouse components; 2 sets of Katie running gear underneath a Lady Anne boiler.

My question is; will the Lady Anne boiler make enough steam to run 2 sets of Katie cylinders?

Jabsteam,

I read this forum on a regular bssis but have now joined it with a view of telling you that this will not work! A good friend of mine tried what you want to do some 15 years ago. The Lady Anne boiler will not cope with producing steam for two 040 chassis. My friend ended up selling off his project. You need a bigger boiler for sure.
Regards John.
Llanwellyn on Youtube please check it out.

[TommyDodd]

A friend has actually built a Tasmanian K1 on 2 cut-down Billy chassis. Originally both ends were powered, from a home-built C-type boiler- which could keep up on a good day. However his line is level and tightly curved so he runs short trains and really doesn't need the power, so he disconnected the rear bogie and now only runs with steam to the front cylinders. A few years later he built a Kitson-Meyer on the same pattern and the same thing happened.

[jabsteam]

Hmmm... I would have liked to use a standard factory boiler, rather that getting a custom boiler built. Roundhouse is the only one I know of that sells factory built boilers.
Does RH make a boiler bigger than the Lady Anne's?

[Llanwellyn]

[quote="jabsteam:94064"]Hmmm...  I would have liked to use a standard factory boiler, rather that getting a custom boiler built. Roundhouse is the only one I know of that sells factory built boilers.
Does RH make a boiler bigger than the Lady Anne's?[/qu4ote]

Hi,
Have a word with D J B Eng. Paul may have the answer.
John.

[GTB]

Does RH make a boiler bigger than the Lady Anne's?

Yes, the #24 boiler and the L&M boilers have about 50% greater water volume, but they still have the same burner and flue size as a Lady Anne. They are also the same dia. as a Lady Anne boiler, so the extra volume comes from the boilers being longer.

Real Garratts have short, fat boilers with large grates for a reason. It's not the boiler volume per se, it's the heating surface that is important. If you want an RH based Garratt to perform the same as two of their locos double heading, then you'll need to have a boiler with twice the heating capacity of a standard RH boiler.

Brian Wilson has built several Ceylon Garratts using RH running gear, but the boilers are his own build and are fitted with two RH burners and two separate flues. You can find You Tube video of two of them running on the RITG layout at the recent GSSU. Look at the 2min. mark, then later at 9 min. and 10 min.

http://m.youtube.com/watch?v=9W4Se8jzgq4

There is also an article describing the construction of a semi-scale K class Garratt based on two Katie chassis in Issue 181, September 2009, of Garden Rail. That has a custom boiler fitted and describes some of the issues with building miniature Garratts.

For what it's worth, a Garratt is on my bucket list and if I get around to doing it, I plan on using a large boiler with two burners.

Regards,
Graeme

[SapperAnt]

I started to build a Mamod one. Had the devil of a job getting both bogeys to run at the same speed. Ended up with the read bogey unpowered...but then it slipped and slid all over the place. oh well.

[Jon Mead]

The Peter Angus Garratts mostly use Roundhouse cylinders and valve gear, but all have bespoke boilers. My H1 has a square firebox with a ceramic burner installed and a multi tube boiler to provide enough heat transfer area. The boiler on the coal fired NGG11 is essentially a Titch boiler.

I have wondered whether a Roundhouse boiler would work on a Garratt, but the issue is surface area in the flue, irrespective of the boiler length or diameter.

[dewintondave]

I'd recommend making your own boiler. I made a two burner boiler for my project, a great learning experience.



Best wishes,
Dave.

Hmmm...  I would have liked to use a standard factory boiler, rather that getting a custom boiler built. Roundhouse is the only one I know of that sells factory built boilers.

[laurence703]

What if he were to use a standard roundhouse L&M boiler but on the bogie units, use a pair of smaller bore cylinders?
This could make up for the smaller boiler size?

[Keith S]

He wants to use Roundhouse valve gear. I think they only make the one type of cylinder for all their engines.

[Lner fan Sam]

Could you not fit a sleeve to the standard roundhouse cylinder reducing its bore?

[LnBmad]

Could you not fit a sleeve to the standard roundhouse cylinder reducing its bore?

If you fit a sleeve you'd then need to make a smaller piston, your sleeve also needs to be steam tight and the ports would need to match up perfectly. Far easier to make your own cylinders if you need a smaller bore.

I'd make my own boiler, or design one and get it made up if you don't feel confident to make it.

[ace]

I may be coming in a little late here but I don't see any reason why you cannot use a lady Anne boiler. My tram uses a lady Anne boiler and makes plenty of steam, so much so that I have to have the gas so low that it is flickering when it's burning to try ant stop the safety valve lifting, it's the same story with my Billy. If you want more steam, just turn the gas up, an eighth of a turn open on the valve and you have a roaring fire! I can have my tram pulling so many wagons that it spins and still have plenty of steam to spare. The only down side is that the boiler duration for a fill may be limited to about 10 minutes if worked hard.

Bearing in mind that you will probably not ever need to work the two loads of cylinders to full capacity to fully drain the boiler of steam.

If your project was mine I wouldn't hesitate in using that setup, in fact I think it would be great.

[JMORG]

His Lordship (ie dad) has made a Salem outline Garratt using 4 Katie chassis'. He used a "Cheddar" design boiler. If anyone remembers the Cheddar locomotives, they are hidiously powerful (one of our chaps had an Ivor that emited BLUE steam!).
We have fitted a Cheddar boiler on one of our Garratts (4 locobox oscilators). The original Roundhouse boiler was struggling to power the 4 cylinders. The Cheddar boiler was added and it's transformed the engine (it's so powerful, it once wrecked its own crank pin!). The original boiler is now on a Garratt powered by an SVS motor.
If you want information regarding the boiler maker, please PM me!

[GTB]

I've been doing some bench testing of a standard Roundhouse boiler, testing the limits of the operating envelope. This boiler isn't a Lady Anne type, but it has the same dimensions. The only difference is the position of the safety valve bush.

Maximum steaming rate with the burner wide open was 17 litres/minute of steam at 40 psi and it burnt 1.5 grams/minute of butane to achieve that.

This gave a run time of 12.5 minutes, 2 minutes to come up to pressure and 10 minutes of running time.

At the bottom end of the operating envelope, with the burner set to the minimum stable flame, the steaming rate drops to 8.5 litres/minute at 40psi and the butane usage drops to 0.75 grams/minute.

This gave a running time of 25 minutes, 5 minutes to come up to pressure and 20 minutes running time.

Note that there is only a factor of two difference between the minimum and maximum steaming rates and the Standard Roundhouse burner performance is closely matched to their standard cylinder size. With the burner set at maximum and the throttle wide open, the cylinders can use all the steam the boiler will make and the safety valve will only just be feathering.

I normally run this particular loco with the burner at the minimum setting (about 1/8 turn on the valve). With the throttle about 1/4 open, it will amble around on flat track with eight four wheel wagons and with the safety valve just feathering.

What this tells me is that a standard Roundhouse boiler can easily steam two Roundhouse size cylinders, with plenty of reserve for steep gradients and heavy loads.

Try and steam four cylinders that size though and you will get a sluggish loco that will have the burner roaring it's head off to even manage to amble around with a handful of wagons on a flat track. It would slow down on curves and be hard pressed to even haul itself up any sort of grade. The run will be seriously reduced to only about 10 minutes before the gas and water run out.

As I've said before there is a reason why real Garratts have a short fat boiler. Looking at the drawings for K1, the first Garratt, the boiler scales out to 2 1/2" dia. by 8 1/4" long. That's big enough to fit two Roundhouse burners, so it would steam four cylinders easily with plenty of reserve and carry enough water to run for about half an hour like other Roundhouse models.

A quick calculation suggests that a standard Roundhouse boiler would be able to steam four 10mm x 15mm cylinders (3/8" x 5/8" for the non-metricated).

Regards,
Graeme