What exactly are these?

[SuperSpeedMaglev]

By 'these' I mean the 'cans' on the smokebox door. I'm just curious.. (I'd like a detailed and simple definition btw)

 

[whitepass]

Two Westinghouse double acting air pumps for the air brakes.

 

[SuperSpeedMaglev]

Thanks.. I'm learning more and more about railways and locomotives!
Just out of more curiosity's sake, what locomotive is this? Under what company? ;P I literally rushed to get a picture and didnt' pay attention to detail..

 

[MeowRailroad]

A Union Pacific 4-12-2, one of the only non-articulated locomotive classes to have 12 driving wheels, or 6 on each side.

 

[SuperSpeedMaglev]

Thanks, both of you guys are great, it was worth waiting for these replies.

 

[JIb228]

If you really want something interesting to know. That round cylinder under the smoke box is a third piston. Air break pumps on the front as the other said. The third piston drove the second axle, which in turn helped drive the rest of the wheels. The valve gear though was linked to the outer pistons via a large set of levers, seen just under the crew members arms. Quite the design of a locomotive and an interesting sound.

(Couldn't find a video of any that sound right, all models. But apparantly someone is building this in 15" gauge.)

 

[bendorsey]

What make this loco particularly interesting is the presence of the Gresley Valve system on the pilot deck to control the center cylinder. This was eventually removed from 8 of the engines and replaced with Walschaerts valve gear. One on the left side and two on the right.

Anyone know why? Obviously the original system worked or it would have been removed from all engines. I'd think it would have been easier to work on as it was easily accessible. Not so with two sets of Walschaerts on the same side. Just curious.

Ben

 

[JIb228]

If I read correctly, it was to replace the barrings in them to be roller's to reduce wear. But I could be wrong.

 

[bendorsey]

If I read the MR Cyclopedia correctly (page 194) there were 88 of these locos (9000 to 9087) but they only did away with the Gresley motion on 8 of them. If it was a bearing problem wouldn't it have shown up on all of them?

Ben (who is guessing too).

 

[nicky9499]

Vaguely recall reading somewhere there was a problem with timing the center piston. When it got bad enough it would actually work against the other two pistons.

 

[SuperSpeedMaglev]

The irony, you ask a question and you start up a discussion, not that I'm opposed it.. :hehe:

 

[nicky9499]

http://www.steamlocomotive.com/4-12-2/

Like other power, wear and "lost motion" developed as miles grew, and in particular, maintenance forces allowed attention to the inside main rod to languish! If you've heard Howard Fogg's recordings of 9009 on his great album "The Big Steam" and think thats what a 4-12-2 regularly sounded like please consider it as virtually totally unrepresentative of their sound. When Howard made his recording, the 9009 was horribly out of time. When badly out of dimension, engines can begin working against themselves and 9009 was probably beating itself to death.

 

[bendorsey]

Its one of the (many) good things about Forums. Lots of folks willing to pass on knowledge other folks don't have (and we all end up learning something).

I asked a simple question some years back (how do you start a fire in a cold engine). After all you can't just fill the firebox with coal and toss in a match, lol. Brought all kinds of retired locomotive engineers and firemen out of the woodwork on both sides of the pond. Was quite a lively and extremely interesting thread.

Ben

 

[daylightguy]

If you really want something interesting to know. That round cylinder under the smoke box is a third piston. Air break pumps on the front as the other said. The third piston drove the second axle, which in turn helped drive the rest of the wheels. The valve gear though was linked to the outer pistons via a large set of levers, seen just under the crew members arms. Quite the design of a locomotive and an interesting sound.

(Couldn't find a video of any that sound right, all models. But apparently someone is building this in 15" gauge.)

That is Correct someone is building a 15 inch 4-12-2. From what I can recall it is being built either somewhere around Chicago or Wisconsin, it's only a chassis at the moment but it should be done within a few years.
https://www.youtube.com/watch?v=uGaSZawmJpw
This is a video of it being tested back in December on the Arborway TT & Northwestern (If your are a fan of minature trains i suggest checking this out it is an impressive railroad). What they are doing is making sure the thing will be able to negotiate the railroad's 200 ft (minimum) radius curves and making any adjustments before getting even farther into the build. I am not sure how far they have gotten since then, since what takes up most of the time is getting all of the parts together (especially the boiler) but as I said before, if everything goes in their favor it should be done within about 3-4 years.

Side note: It will most likely be based off the 9000 class minus the third cylinder.

hope that helps.
Martin.