3/4"Kozo A3.

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: Harold_V, WJH, cbrew

Posts: 159
Joined: Fri Jan 02, 2009 6:51 pm
Location: worcester,ma

3/4"Kozo A3.

Post by elm53 » Thu Jun 23, 2016 3:50 pm

So,...has anyone who built this engine actually been able to run continuously with it (not once around and oil,fire,wax) ,the once around again? And if you have,could you post a video of it? The 3/4"scale version , NOT the 1"" or the 1 1/2" scale versions. Not on air,not on blocks,not in the shop,but on the track with a load behind it.

User avatar
Posts: 211
Joined: Fri Sep 03, 2004 8:08 pm

Re: 3/4"Kozo A3.

Post by backyardrails » Thu Jun 23, 2016 7:53 pm

I owned an A3. Keith Woods finished it for me. I sold it to a member of our club. It runs just like a Raritan. I have Raritan as well. Nice little engine. I am sure there are a few people on this board that can attest to it.

Posts: 366
Joined: Tue May 22, 2012 7:50 pm
Location: Oregon

Re: 3/4"Kozo A3.

Post by jcbrock » Fri Jun 24, 2016 10:50 am

We can likely get Greg Easter to try this at the St Croix Small Scale Meet and report back. We're going to have to hand him jugs of water as he rolls by and see if he can refill his tank on the fly, as he has built an A3A with no tender.
John Brock

Posts: 1001
Joined: Thu Apr 26, 2012 10:15 am
Location: Tennessee, USA

Re: 3/4"Kozo A3.

Post by Pontiacguy1 » Fri Jun 24, 2016 11:11 am

If it can keep up the steam when it is pulling a load, then you should be able to run it pretty much as long as you can stand it. As long as you can keep oil, water, and fuel in it while moving, then you should be able to run. You shouldn't have to oil it but a few times per day, so that shouldn't be a big issue. You might have to add an auxiliary water tank if you want long continuous runs, though.

What I think you're really asking is does this thing steam well enough so that you don't have to stop every once in a while for it to 'catch up' or to build up the fire. I've seen locomotives that wouldn't steam too good do that... They run the blower, sit there for 4 or 5 minutes, get about to popping pressure, then take off around the track. When they come back in after a lap, they would have 50 or 60 pounds on the gage, and would repeat. A well designed and built locomotive should not do that, if the engineer knows how to fire it. Something was wrong with the fuel, draft, smoke box leak, etc... on those locomotives and it needed to be fixed.

If it can make enough steam so that it doesn't have to stop and catch up, and if you can fuel it while it is moving, then there should be no reason you need to stop... until your butt goes numb!

Steve Bratina
Posts: 987
Joined: Tue Jan 16, 2007 9:39 pm
Location: Cambridge Ontario

Re: 3/4"Kozo A3.

Post by Steve Bratina » Fri Jun 24, 2016 2:35 pm

I think what Mr Elm is asking is " has anyone built a successfully running 3/4" model of the A3?" I have seen several that were quite nicely built but they soon were back in the bay because of either no water, no steam or some othe malady. I never saw an engineer with one of these engines rubbing his keister cause it fell asleep.

Posts: 159
Joined: Fri Jan 02, 2009 6:51 pm
Location: worcester,ma

Re: 3/4"Kozo A3.

Post by elm53 » Fri Jun 24, 2016 7:13 pm

Bernie,thanks for answering my question.I expected to hear from you,as I knew you had one.
Mr Brock,please let us know how it goes with Mr Easter's locomotive...video maybe ..along with some of your clubs recent highline rebuild.
Steve (Mr.Steam),Thanks for translating my question to proper question asking form.

Wayne Davis
Posts: 103
Joined: Mon Sep 03, 2007 10:19 pm
Location: Creston Iowa

Re: 3/4"Kozo A3.

Post by Wayne Davis » Fri Jun 24, 2016 7:27 pm

In the 2016 small scale meet topic there is a video of an A3 as a tank engine. Is this what you are wanting to see?


http://www.chaski.org/homemachinist/vie ... 85&start=0

Posts: 159
Joined: Fri Jan 02, 2009 6:51 pm
Location: worcester,ma

Re: 3/4"Kozo A3.

Post by elm53 » Fri Jun 24, 2016 7:39 pm

Hey Wayne,that ANSWERS my question comletely. ThanksWayne,for a short accurate answer. Our agents will be standing by to tell you what,you have won!!! :mrgreen: :mrgreen: :mrgreen: :mrgreen: :lol:

Posts: 49
Joined: Mon Jan 19, 2009 10:53 pm
Location: Minneapolis

Re: 3/4"Kozo A3.

Post by GregE » Fri Jun 24, 2016 9:00 pm

Hey that's me!
I had my A3a in steam for about 3 hours that session- I was getting a bit stiff in the keister towards the end...
Mine is a saddle tank, so not as much water as the tender version, but can run about 3 laps of the St.Croix track on the water I have-almost a half mile.
That does depend on load- that was just pulling myself. If I load it up, coal and water use go up.
I think it is more sensitive to coal type than locos with larger fireboxes.
I so far have had great luck with welsh coal- lots of heat and easy to keep the fire hot. Works well mixed 50:50 with less great coal to save money.
I also had great results with a batch of leftovers of some fast burning bituminous- smoky and hot.
Other types can be hard to keep pressure up.
Overall I find it to be a well balanced design. The axle pump provides plenty of water, the fire breathes well with the flue design, and given a good fire it provides the steam needed for extended running.
Greg Easter

Posts: 540
Joined: Sun Feb 22, 2009 9:21 pm
Location: massachusetts,usa

Re: 3/4"Kozo A3.

Post by steamingdon » Wed Jun 29, 2016 6:34 am

So am I to assume that Greg`s is the only loco that actually runs? :?

Posts: 38
Joined: Sun Oct 12, 2008 7:45 pm
Location: Montreal QC

Re: 3/4"Kozo A3.

Post by UKlocoNut » Wed Jun 29, 2016 12:40 pm


As Bernie stated, I finished one for him, the loco runs nicely but only after a few modifications, larger ram on the axle pump, improved tender hand pump, water glass re-plumbed.

I have done several laps of MLS behind the loco during testing.

Its present owner is not comfortable to fire on the fly so he does half a lap then stops to stoke up.

Fiddly machine, not really a beginners engine.


Posts: 159
Joined: Fri Jan 02, 2009 6:51 pm
Location: worcester,ma

Re: 3/4"Kozo A3.

Post by elm53 » Wed Jun 29, 2016 5:36 pm

The plot thickens! Thanks for the input on the mods. Don and I suspected a bit of Wood magic.

Post Reply