Hello everyone.
Where I am working there was a opportunity to speak with a mechanic that was swapping out a Caterpillar 3524 from a 797 haul truck. He said that the engines are expected to perform for 14 to 15 thousand hours before overhauls. So my question is what kind of life expectancy can you expect from a GE or EMD diesel engine in a modern AC engine? Basically asking about the 710 and the GEVO diesels.
Thank you
I had the opportunity to speak with the GE reps in Denver whilst on an escort move. My question pertained to the turbo rebuilding/replacement on the 7FDL series. They said the turbos should be rebuilt when the engine is overhauled, every 7 to 11 years.
The ALCo 251 manual has one sentence of direction for 8 years of use: Remove and rebuild engine.
From a builder’s plate of a Tier I Dash 9-44CW: “EPA Emissions Useful Life is the earlier of 33,750 MW-hours, 10 years or 750,000 miles per 40 CFR Part 92.9”. Seems reasonable that this is about the average prime mover lifespan.
High speed diesels wear faster and require more frequent overhaul and replacement.
Hello,
Thank you for the replies. It is interesting to read what the railroads expect. This would also explain why the horsepower output per cubic liter is for a prime mover in a locomotive is rather low specially when compared to vehicles on the road. Fascinating information.
Thank you
Frank
Just imagine what ‘hot rodders’ could get out of a locomotive diesel for power if they tried the tricks of the hot rod trade. It may no longer be Tier compliant but it would be fun to see!
I wonder what a 2-stroke on nitro would sound like…
Boom.
I’ve heard Alco service people say that an Alco will go much longer between rebuilds than an EMD, but it does need a bit more tinkering in between.
Cheers
Steve
NZ
Well, I have seen some tempermental EMD engines that needed a shot of starting spray to get them running and if you sprayed too much in there it sounded like it floated the valves.
Actually you do not even require hot rodders to get huge numbers. In order for the diesel engines to have the longevity required by the railroads they produce relative low HP per cubic liter. The 710 only produces about 23 hp per liter. The Dodge diesel in the half ton pick up produces 80 hp per liter. As a result if you would get the 710 to produce power like the diesel in the pick up truck you would be looking at about 14,880hp. How long before the engine would blow up? Probably not long.
In a similar vein, I read an article in “Air & Space:Smithsonian” some years back about adapting automobile engines for service in light (4-seat) airplanes. The difference in the duty cycles was a major stumbling block as aircraft engines spend much more time at full throttle than automobile engines.
The question for the 10 years is that in service or a hard number of years ? Thinking of all the locos stored at present for who knows how long ?
That may be a function of how they are pickled.
Don’t forget the carriers maintain extensive records on the maintenance and repairs that have been applied to each locomotive in their fleet - they make their decisions going forward based on the ‘big data’ contained in their locomotives history.
If the words are reproduced exactly from the decal, “whichever comes first, 10 years or 750,000 miles”, then it is a “hard” ten years and the engine would have to be lifted and overhauled, or at the very least retested to ensure that it still met the regulations. However reading 40CFR Part 92.9 should clarify this.
M636C
And to simplify this discussion here is the text of Part 92.9 for you.
The quote is exact, and I can post the decal tonight if anyone wishes.
The challenge would be using all that power. On a six axle 4400 HP locomotive, the traction motors come in just over 700 HP per. On a 14,880 HP locomotive, they’d approach 2,500 per axle. And you thought the GP40’s were slippery…
Of course, if you could use that power in mother/slug configurations with six axle units, you’d be down to 1,250 per axle, but that’s still pretty hot.
Of course, that assumes that the prime mover could survive such a mod…
Over time an engines cylinder bores oval out at the bottom near the crankshaft as that’s where the most amount of side thrust is. The more wear and looseness that an engine exhibits would bring it closer to a damaging failure. I’d guess the cost to rebuild a prime mover could buy a cheap house. I once dismantled a Ford/IH 6.9 diesel V8. When I pulled one head off I saw 3 Pistons. The 4th piston was in about 50 pieces in the pan. The rod was bent and two sides of the cylinder was pushed out. When I worked at a Napa parts store a guy brought in a piston from a drag motor. The stem of a valve went through the head of the piston. The valve flipped 180 degrees before piercing the piston. It was cool to look at.
Nitromethane in a diesel? Burns slower than other fuels, turns oil into molasses. Nitrous Oxide? Whiing, boom! The more massive the rotating assembly, the slower the piston speed has to be. A lot of hot rod tricks would not work in a huge diesel. I think airflow, and boost, have been pretty well figured out by the big players…
This is interesting for another reason in this hypothetical discussion: part of the ovaling effect is associated with thrust reaction between piston and rod, and part of it with inertia forces in the rod (which is a factor of relatively high rotational speed). There’s also both average and peak tribology failure between piston components and cylinder bore, particularly at high peak machine speed.
In the application of nitromethane or other ‘advanced fuels’ to a locomotive engine, the horsepower gain will not involve operation at dramatically higher rpm (as it usually does with drag or race motors, where horsepower climbs with increasing rpm well above the peak of the torque curve). So we have to be talking about dramatically higher – and I mean dramatically higher – peak and mean effective pressures in an engine that isn’t built of Formula One grade exotic materials to be able to spin at the required rpm to make “all those horsepower” the usual way.
There are also some interesting potential questions about injector performance to get full fuel injection into the corresponding swept volume and then full charge mixing, polynucleate ignition, and (reasonably) full combustion at that high an rpm … assuming we are continuing to try to run this as a compression-ignition engine. (The situation gets worse, far worse, if we plan to meet Tier 4 final emission standards, but neither the ‘willing suspension of disbelief’ or my ability to keep tongue in cheek without biting will survive taking that discussion too far…)
A potentially interesting discussion might be what form of engine that would fit within packaging limits on a locomotive could actually produce this power density on an ‘appropriate’ fuel, although I know this is a wide diversion