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Q1 update

Second Q1 now track tested

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nick feast25/06/2012 17:38:33
75 forum posts
7 photos

The loco that I build alongside the recent ME series has now been completed and has been through a couple of months of track testing and the usual ongoing R&D that goes with every newly built steam loco. It is shown below in original Southern spec with none of the minor changes that were applied as the locos came into use. Also has displacement lubricator instead of mechanical pump, in line with the prototype C23.

I hope to write up all the fine tuning over the next few months for the editor's consideration, but rest assured there were no significant deviations from the published drawings! The main change was getting a better reading on the water gauge glass.

Fiddling with the blast nozzle size has resulted in a loco will make steam on a level track on light load, but will still pull like a demon when openend up! I have been very pleased with the self reguating character of this loco, so that once the train is under way ( weighted 7 1/4" gauge bogie trolley with driver plus one or two adults) the regulator and cutoff can be set, around 40% full movement in both cases, and the loco will merrily circulate the BDSME track of 1/3rd of a mile with the occasional shovel of coal and a bit of injector to back up the tender axle pump. Last years's IMLEC contestants will confirm it can be a tricky track. On several ocaisions I've done a full lap with arms folded, just to show off! You need to fill the firebox and boiler in the station first though!

Exhaust sounds a bit asthmatic when starting off, but sharpens up when rolling and as with the first loco, runs very smoothly even with nominally very short cutoff (with joy gear the cutoff is longer than with most others I gather).

Look forward to seeing another one completed soon, there must be one nearly ready!



John Alexander Stewart25/06/2012 22:34:54
747 forum posts
51 photos

Good work!

I'd love to see the locomotive updates in print - if you need any arm-twisting of the editor, just ask.

Another JohnS.

nick feast26/06/2012 17:19:34
75 forum posts
7 photos

Another point I forgot to mention in the first post was the weight.

The first loco clearly had a lot more power than it could use, so I felt more weight in thesecond loco would be good idea. It tipped the (bathroom) scales at 25KG.

I added as much weight as I could in places it wouldn't show, e.g a solid steel block in place of the front mounted oil tank, thicker ashpan material, heavier cladding steel etc, and weighed the new engine in at...............24.5KG! The difference being a smaller firebox on the second engine, closer to scale. Forget lagging the boiler with lead, it's too high and will have the loco off the track on a bend. Working sanders anyone?

John Alexander Stewart26/06/2012 19:47:34
747 forum posts
51 photos

Any changes to the drawings? I ordered from Polly back March-ish timeframe.

Random comment - drawings are not copied to scale from what I saw; so one can not just take measurements from them, despite what Nick's comments on drawings state. (eg, Nick may have added a "drawn full size" but my copies do not measure out correctly)

Not a big deal, but beginners may be a bit confused.

Another JohnS.

Stub Mandrel26/06/2012 21:56:43
4306 forum posts
291 photos

Hi Nick,

I must admit the 'elegant lines' of the Q1 make it much more interesting to me than most locos!

Can you remind me of the boiler dimensions?


nick feast27/06/2012 08:25:29
75 forum posts
7 photos

OK after 2 completed locos and feedback from those keen enough to check this sort of thing, it's time to do a final review of the drawings. I will make all the amendments that have come to light and update the masters so that anyone buying a set of drawings from Polly in future will have known errors removed. A nice job for the weekend. The only critical change is the positioning of the Joy Gear slideshaft pivot mentioned some time ago, this was rectified by rev 5 of the frame drawing issued in Dec 09.

I draw full size where possible, get the drawings scanned onto disc and Polly print them in a convenient format, which may well not end up as full size. Scaling from the drawings can be done to get approximate dimensions but I've always been told it's bad practice.

Boiler has a capacity of 2 litres full to the brim, grate area 54 cm2, WP 80PSI. Which other dimensions did you need Neil?

Edited By nick feast on 27/06/2012 08:28:09

Stub Mandrel27/06/2012 21:35:51
4306 forum posts
291 photos

Thanks Nick,

I can't afford a bought boiler, so if I do make the jump to trying a live steam loco, it will have to be within my capacity. So far my biggest & most complex boiler is a centre flue one about 3 1/2" diameter by 7" tall. I could do bigger, but not HUGE!


John Alexander Stewart28/06/2012 13:24:10
747 forum posts
51 photos


I really like this Q1 design, so apologies to Nick for pushing it all the time.

I'm literally just finishing a Martin Evans' "Ivatt" boiler, and the Q1 is about the same size. It's managable with a Sievert torch, although I now have a "TurboTorch" acetelyene torch with the "A-32" burner, and it's great.

Some club members are building 7-1/4 boilers in copper and they are huge, and expensive - or should I say, "more expensive" than mine.

I have 2 running 3-1/2" gague locos, a Tich, and a big 2-8-2. I think something inbetween, like the Q1, would be great; not too big, not too small, easy to handle, cheap-ish to construct. I have a 95% finished "Kozo Shay" that has so many bits and pieces that I have currently lost interest in it; the Q1 is dead simple in comparison.

I also really appreciate Nick's instructions, and his humour. It's the best construction writeup in a long time, in my humble opinion. Get, and read, the articles if you can.

Lets see: ME 4353 through 4405, every issue or every second issue. Do you have a digital subscription?? If so, you can see them there.

Another JohnS.

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