Garden Railway Forum

Today was the day! Steam test time. Two runs on the workbench in the garage this afternoon, without the chimney extension or the smokebox door so it could be fired by the blowtorch.

1st run with half a gauge glass of water seemed very brief until the water was out of sight, but the 2nd run with a full glass of water lasted about 30 minutes of gentle ticking over. First impressions, it runs wet.

The lubricator worked well on the 2nd run, I started it off without the lid, trickling steam over the cold oil, then put the lid on. It's connected to the reverser by a silicone tube, I could see the different flow when slowing or stopping the engine compared to the running, there's a reverberation when running. After the run there were plenty of oil splatters on the boiler shell and a fair amount inside the smokebox.

There was a gentle leak from the blower valve throughout, which will not be a problem when the blower is connected.

Very nice Dave, bet you can’t wait to get it on the track.

When you say it runs wet is this just exhaust condensate?

It's lovely and I really like the big oscillating engines. I like running live steam trains - they don't have to be exact scale models to float my boat.

That really doesn't dissapoint me for an oscillating engine, or any live steam engine actually. It runs really slow and smooth as silk. Good job!

Second whats been said above. Very smooth.
Grant.
PS how do you hold steam, in order to be able to trickle it

Thank you guys! Yes there was lots of exhaust condensate. I'm thinking of adapting it so that I can gas fire it on the track too. I quite like a toy like caricature look, hence the brass roundhead screws on the smokebox simulating rivets.

I trickled steam from my fingertips via the regulator

Nice job on that Dave, I have been watching with interest.
I have a copy of the plans filed away waiting for the day when I can get the workshop set up.

I am quite surprised that no one has ever built these commercially.

A few more photos to complete the scene

Water pump with bar to stop the ball seating


Nearly completed water pump


Fusible plug for the top of the firebox, filled with electrical grade soft solder


Wheels finally being Loctited to the axles, using the aluminium spacers for the back-to-back measurement


Turned turtle to make the steam and exhaust connections


Looking into the abyss/lubricator after the steam test

What is the fusible plug for the top of the firebox for?

tom_tom_go wrote: ↑Tue Jan 09, 2018 7:45 am What is the fusible plug for the top of the firebox for?

Inner firebox, in case the water gets so low that the crown gets seriously hot. I wanted to try all the bells and whistles.

Ah that make sense!

Very nice. I'm surprised by how slowly you can run it. I've always assumed that oscillating cylinders are the 'poor relation' in the steam engine hierarchy ( maybe because I associate them with lower priced models). I've therefore always assumed they would be the least controllable. You've certainly disabused me of that view. Is there any physics to explain why, mechanically, they might be more controllable - eg less friction? Or is it down to careful design and manufacture?

Rik

Rik, I think the reason for your thinking is you are probably used to seeing locos with single acting cylinders, that need to run faster as they only have two power strokes. Dave's loco has double acting cylinders, therefore effectively four power strokes which dramatically aids smooth low speed running.
Grant.

I've owned both an IP Jane and a Mamod I made new cylinders for. Both had double acting cylinders and would run very slowly and smoothly.

ge_rik wrote: ↑Tue Jan 09, 2018 8:41 pm Very nice. I'm surprised by how slowly you can run it. I've always assumed that oscillating cylinders are the 'poor relation' in the steam engine hierarchy ( maybe because I associate them with lower priced models). I've therefore always assumed they would be the least controllable. You've certainly disabused me of that view. Is there any physics to explain why, mechanically, they might be more controllable - eg less friction? Or is it down to careful design and manufacture?

Rik

Hi Rik, the secret is having the big cylinders, these take longer to fill, and these larger scale locos have more momentum/mass. After the success of the large De Winton (in my thumbnail image, it just walks along), I wanted to do a more conventional loco. Today I saw a lovely model 16mm K1 Garrett being test run on blocks, it was either thrashing away or stationary, at one point he revved it up to about 1000 RPM

Busted Bricks wrote: ↑Tue Jan 09, 2018 10:51 pm I've owned both an IP Jane and a Mamod I made new cylinders for. Both had double acting cylinders and would run very slowly and smoothly.

So, did your cylinders havd finer tolerances than the originals?

Rik

ge_rik wrote: ↑Thu Jan 11, 2018 5:04 pm So, did your cylinders havd finer tolerances than the originals?

Rik

They must have had that - the originals were so worn out steam was leaking past the pistons! I think I did the trick was a homemade 3-wicks meths burner - just the right amount of heat to keep it in steam but not blow off all the time which inevitably means dousing the fire on a Mamod.

Been making lots of slow progress. There's so much umm-ing and aargh-ing when dreaming up a loco on the fly. I eventually committed to producing a one piece foot plate. It's all hacksawing and filing. With pieces so long I have to measure using a steel rule.

I've got a lifetime's supply of 1.6mm steel. This is a 300 x 600mm piece


One evenings cut...


Finally cut out ready for filing to size


Nearly finished with cut-outs for smokebox and firebox coming along nicely

Nicely done Dave, looks like it has been CNC'd as well.