Western Railroad Discussion > SCRM FM H12-44 Tunnel Motor

The prime mover has had all of its hand covers removed for cleaning. That allows a look right through the engine. The piston rod is showen vertically and the crankshaft balance lobes are very visible. This is a look at a real tunnel motor!. The crankshaft and pistons rotate at 14 times per second when the engine is at full speed of 850 RPM. That's thousands of lbs rotating. And its very smooth. The balancing was done very well by FM. But all kidding aside, the engine has now been tested to 900 HP for 45 minutes. That gave the exhaust system a chance to finally heat up enough to burn out any loose oil and carbon. Essentially everything ran great. The only problems were with some rubber drain hoses that had been installed on the exhaust snubber drains. They started to melt. Those were on the locomotive when we got it 30 years ago. They will be replaced with the correct steel pipes which will stand up to the exhaust heat.

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Dave,

Thanks for the update.

J. Ferris #690

Very intersting, thanks for posting.

Years ago I was at Hunters Point in San Francisco.  A DRGW GP40 was pulling gondolas of pipe out of the yard and stalling.  The traction motors overheated and started a grass fire underneath the engine, though the engine seemed to still work okay.  But they couldn't get the trains started, so the crew called the Railroad Museum (Pacific Locomotive Association?) which kept their equipment there.  Their H12-44 was attached to the back of the train and with a confident hum of the engine got the cars moving.  Once out of the yard, the GP40 took the cars out to the mainline.  But the H12-44 followed in case there was more trouble.

Stan Praisewater

We've had a chance to run the H12-44 a little. The initial feeling is that it is very powerful for its size. From what I gather, the Opposed Piston engines produced a very high level of horsepower compared to the weight of the engine. Of course the problem is that the design, using an overhead crankshaft and two sets of pistons, is so different from any other Diesel engine. Its our only OP engine at the museum and we are still learning how to deal with it. Its a very odd piece of equipment to say the least.

I had the "pleasure" of working with two models of FM's while in the Coast Guard. The four FMs in my first ship  was an old Navy Seaplane tender. Those FM's were direct reversable, two FMs per shaft. My second ship was a unique ship built in the early sixties with two turbocharged FMs in the middle of the engineroom with two Pratt and Whitney "jets" positioned outboard of the diesels. In both cases these diesels were designed to operate normally at flank speed when in transit at sea--"balls to the wall". The turbocharged FM was routinely operated at 900 rpm. The temperature between the diesels at flank speed was 122 degrees! No smoke was visible from our stacks when underway. The newer ship had controllable pitched screws made in Europe! I will never forget the time aboard either ship nor the screaming FM's!

My Dad worked for F-M in their Dallas office on Carpenter Freeway, selling engines and gas compressors
to the Texas oil & gas industries..  He said they were a tough sell out in west Texas due to competitive pricing issures
but that those that did use them really liked them.  

Here's a training video put out by the US navy in World War II. It describes the engines used in diesel submarines. They discuss two-stroke engines designed by Winton (EMD), Fairbanks Morse, and HOR (Hooven-Owens-Rentschler). The latter were so unreliable in service that they gained the nickname "whores".

https://www.youtube.com/watch?v=cxhakWu75Rc

Looking at the FM H12-44 all these years sitting at Perris,  I always thought, it would be a bear to restore. Although it is a lot of work, I am really surprised at the results
It looks like it might end up being a good running unit, and once its repainted, a very nice example of the operating fleet of diesels at the museum

Most probably the FM locomotive will never be used in day to day operations. We have gone far enough in its restoration to know that oil being fed into the exhaust system is, and will be, an ongoing problem. We think we have a way to live with it but most probably it will relagate the locomotive to special operations only. Of course we hope it doesn't end that way but that's what seems to be the future for it. However, the plan is to go ahead and finish the restoration and make it an operational piece of equipment for the museum.