Yes definitely an inch and a half scale but it could either be laid out as a 7 "1/2 or a 7 "1/4 7 and 1/2 is what took root on the west coast and back to the Midwest the East Coast has the seven and a quarter

your not wrong as someone that builds these things for a living i would say 7.5 gauge to.

The Yellowstone is a simple articulated locomotive, not a Mallet.

In fact, the last main line steam locomotive stood up on the rails in N. America was #2200 Norfolk & Western Y6-b, which was a compound locomotive, so NOT simple steam in both cylinders. The Y Class had 'booster' valves to admit full pressure steam directly from the boiler, but only when lifting the train from a dead stop. After something like 15 mph, the engineman switched off the booster and the engine reverted to compound operations with the much larger front pair of cylinders receiving expanded/cooled steam exhaust from the rear cylinders. Both the Southern Pacific and the DM&IR called their articulated engines Mallets, but this is strictly incorrect. A Mallet, by definition, was always a compound articulated pair of engines under one boiler.

Correct about Mallets, but an articulated locomotive is simply any locomotive with a hinged frame. Mallets are articulated: they're articulated and compounded. There's no sense in which a Mallet is not a "true" articulated locomotive: they have the defining characteristic of a hinged frame.

another design worked better then the simple mallets called the Garratt the garratt is very complicated but they where not as powerful hwever they spread there weight better and could run on very light track

@@IndustrialParrot2816 Garratts are a whole other kettle of fish, although the first K1 was a compound.

@@johnkuzma7066 actully only 3 or 4 garratts were ever built as compounds

@@IndustrialParrot2816 yes, with the long distance between the cylinders it wasn't that feasible because the steam would condense in the line and be wholly ineffective once it reached the LP cylinders. Atlest on the K1s (only compound Garratt I'm familiar with) the cylinders are facing one another to reduce the distance (rather like a Kitson Myer), this has the problem of reducing the available space for the firebox tho.

@@johnkuzma7066 the simple expansion garratts worked better but the long steam tubes were a minor issue

i know maybe they do something something specail for an anneversry or something

Boiler would need inspection and testing before running. On the first fireing there would be all sorts of leaks to troubleshoot.

@@devinholland2189 True, but it would be nice to at least try. I know someone who has built an Allegheny locomotive in 7-1/4 inch and it's nice to watch. There is a video of it if you search "C&O Superpower QSMEE"

Thank you!

i would tell you but i am not familer enough with the milwaukee road and i don't much about their electric locomotives

@@IndustrialParrot2816 then why answer?

@@jamesm6638 i don't know i don't get to about this stuff much

@@IndustrialParrot2816 generally if you don't know the answer to something, you don't answer... especially when they weren't asking you directly... common sense really

The maintenance to keep a model like this running is huge. A friend now owns the Tom Miller Big Boy. It is most definitely not a daily driver.

Here ya go! kzfaq.info/get/bejne/gbpybNaJtZi3Y4U.html

Have to oil it regularly

Right I forgot about that… that’s gonna be a problem

Here ya go: kzfaq.info/get/bejne/gbpybNaJtZi3Y4U.html

But if A. Mallet of Switzerland invented the first articulated loco, then they are ALL Mallets (or pronounced 'mallies' by some aficionados and modelers). Power distribution differences don't change this fact..

@@MarkInLA Mallet's invention was specifically a compounded articulated locomotive. The point of the compounding was that it only required low-pressure steam through the flexible joints. Putting high pressure steam through those joints required further innovations.