Innards and Repairs of an MTH UP9000

I don't think the tape on the rear coupler is necessary as there is no axle under it like in the photo.

I'm not familiar with the loco. What does the third piston do.

The real  UP 9000 had three steam cylinders for extra power and better use of steam. The MTH model replicates it and it actually moves in synch with the left and right cylinders. Lionel's Legacy UP 9000 model does not have a working 3RD cylinder.

The UP 9000 is a compound loco.  The inside cylinder is a high pressure cylinder and the two outside cylinders are low pressure cylinders.  The inner cylinder exhausts into the two outer cylinders.  Compound steam engines generally have a higher thermal efficiency than simple (non-compound) locos.  The penalty for compound locos is complexity.  

Strictly speaking, a Mallet loco is a compound, and the ones in this country had huge low pressure cylinders.  The rear cylinders on a Mallet were high pressure cylinders and the front cylinders were low pressure cylinders.  The low pressure cylinders were usually 36 inches in diameter.  These huge cylinders created severe balance problems because of the weight of the piston.  Speed on the Mallets was usually limited to 30 mph due to the balance problem which would cause damage to the track at higher speeds.  

The UP Challenger and Big Boy are NOT compounds

Awesome job! Very nice locomotive.

Another great photo essay although I have to say, it does not reflect well on either of the big two O gauge manufacturer's QC that you have issues like this with new or practically new engines.

I have the Legacy version of this engine without the working valve gear. Thinking about your slow speed performance issue, I'm afraid I have always found PS2 engines to be jerky at anything below 5 scale mph - a techie told me it was a system defect which I have always thought has to do with the tach reader.

nice recovery and documentation of the process. Thanks for sharing

Doesn't the MTH version have opening cab vents on the roof?  Also, does the cross bar on the pilot (not sure of the techinical name) move when in motion?

Though not a Union Pacific Type, as the 9000s were known, I recently picked up a 3rd Rail 4-10-2, 3 cylinder.  It's fantastic to watch the 3rd cylinder action and all the movement on the pilot.  Just a beautiful locomotive!

Thx guys for all the nice comments. I hope these threads and others may help some one.

You know, I like to tinker, but if I did not like to tinker, I'd be P***** off to no end with these NIB issues...

Although I guesstimate the failure rate of locos I have (mostly steam, Diesel I have had 1-2 issues so far) is about 8%....Not sure if this is hi or low?

Mr. Water is correct; the 9000's were 3-cylinder Simples.

====

I have the Lionel version (TMCC); bought lightly used. Smoke does not work (this was made

when Lionel pretended to have smoke units) and the 3rd cylinder gear on the pilot

is not a functional design on the Lionel model. Wish that it were.

But, runs and sounds nice. The 9000's were such an impressive design, actually considered high-speed freight locos, and were so good that even after the 4-6-6-4's knocked them

down the totem pole a bit, they did not replace them and they lasted pretty much until

the end of UP steam, I believe.

I'm not a UP fan, but these things (and the gas turbines) have always attracted me.

Thx man.

Yes, cross bar does move in synch and one can see it well. And yes, it does have two opening cab roof vents

Thanks to Sam for posting the photos and information.

The 9000 is an extremely impressive piece of machinery, and even more so if you can get two or three of them together. We had a "9000 day" at the toy train museum a while back. The sight and sound of two of them side by side is something to remember!

I got mine secondhand off of eBay. The seller wasn't a train guy; he was some goofball in LA whose usual line was skateboard parts. He shipped it to me in the purple shelf box, all wrapped up in clear packing tape and a label slapped on - no outer carton at all! Luckily the package arrived intact and the locomotive ran fine. 

I've had two of them - the MTH one and the 3rd Rail version. The 3rd Rail engine has more detail and is a bit better looking, but the MTH is a much better engine in operation. I decided to sell my 3rd Rail engine and get an MTH one after running mine side by side with a friend's MTH version on his layout. The MTH handles switches and 072 curves much better. The 3rd Rail engine, which has flanged wheels on axles 1 and 6, drags on 072 curves. The MTH engine, with flanged wheels on axles 1 and 5, handles the curves much better. Sound and smoke are vastly superior on the MTH unit. Both have the working 3rd cylinder, valve gear on the pilot, and cranked axle. The MTH engine has a very distinct 3-cylinder sound to it - you can hear 6 chuffs per rev at slow speeds. 

Here's a pair of MTH 9000's running together at the Gadsden Pacific Toy Train Museum. I wish I'd had a video camera that day! 

Here's the same pair of 9000's running double-headed at the home of the friend who owns the other engine. 

Great pix SWH (is it ok to call you as such?)...

The 9000 for me is not so beautiful it actually makes it beautiful for me

Nevertheless, it is an awesome and unique engine and the MTH rendition with a working 3RD cylinder is great!