Diesel-engines for large ocean-going ships have much bigger cylinders than locomotive-engines. Does anyone know why locomotive-builders do not use reduced shipping-engines - let’s say four-cylinger-engines - to propel their locomotives instead of designing eninges with 16 or 20 small cylinders? This would mean less moving parts and the ability to burn the cheaper bunker-oil.
By the way, does anyone know why the wankel-engine never made it into the raisoad business (locomotives or DMUs)? Today, it is absolutely reliable, unlike the engines in the early 60s. And it is best if it runs at full throttle.
I would guess that locomotive and ship engines are generally about the same proportion comparing the cylinder size to the overall engine size. Here is a nice video of a ship’s engine starting with the control room, then to the top of the engine, and working down to the bottom. It looks to be about three stories high:
…They most certainly are…By Mazda. Saw two of them this morning…Sporty models. "Zoom…Zoom…Zoom…
GM just about produced them in Vegas back about 1976. Pulled the plug on them at the last minute. We had several Performance Vegas in our Lab…{BWA}, that looked production ready right before they canceled the program.
Current day true Marine diesels (those used in ocean going vessels), measure their bore and stroke in feet, not inches. Where smaller diesels are needed for marine propulsion, they adapt railroad originated prime movers for the most part. I recall being on the New Orleans waterfront as a child and wondering where the train was…as a tug boat was moving a tow of barges by on the Mississippi…the tug was powered by EMD 567 diesel engines. There is a bigger market for railroad diesel engines of the 4000hp range than there are for any other application at this range of power, as a consequence most applications will adapt the railroad derived engines.
Back in the early days of dieseldom, Fairbanks-Morse adapted their marine designed opposed piston engine for railroad operations. While the engine performed reasonably well, the continual start/stop; speed up/slow down, form of operation in the railroad environment wore the engines out prematurely and they became a maintenance nightmare.
Several possibilities at least. First off, maintenance. While it is true that maintaing four very large cylinders and piston/rod assemblies might result in some small savings, handling those parts would cancel that – marine engines and their subassemblies are large. To put it mildly.
Second, the ability to burn Bunker C is much more dependent on the setup of the injection system and the ability to keep the stuff warm enough to flow than on the size of the cylinder. In fact, marine engines are normally started on diesel, and most of them run on diesel for maneouvering. It’s just at sea, where you have umpteen days of constant speed operation, that you switch to Bunker C. The added complexity of the heating system for the fuel would be a problem (to put it mildly) and you would have to have diesel available as well – meaning two sets of fuel tanks.
Third, marine diesels are designed to run at pretty much constant rpm and power; they are much less able to shift power quickly than a railroad engine (which is why the smaller railroad type engines are used on tugs and harbour craft, besides the heating problems noted above).
Fairbanks Morse, still produces ship engines. For a number of years they produced locomotives using their opposed piston engines in a smaller size for locomotives. They are very powerful. When the H24-66 Trainmaster came out in the early 1950’s it was the most powerful locomotive available. The SP ran them for 30 years on commuter service on the San Francisco Peninsula during the day and pulling freights at night.
…Not sure we’ve seen any advantages from the Wankel yet…Purported to be performance from fewer parts and smoothness. But I suppose it hasn’t risen to the point to where it is pushing the current 4 stroke I C engine back that is still the engine of choice. Wankel has had some sticky problems to solve.
One note: Years ago I personally experienced extreme performance from 3 rotor engines {small physically in size}, in prototype form and engineering cars both in the U K {a scary ride on a Motorway}, to here at our Lab as we worked with some regarding the use of our transmissions.
F-M’s opposed-piston engines performed admirably in marine applications. With steady operating speeds, clean sea-level intake air, and unlimited cooling water, they worked out great.
For locomotives, F-M tried to stretch the horsepower output and, of course, put the engines in an environment with plenty of negative variables. For one example, UP helper service on stiff grades over 4000’ elevation in the hot, dusty California desert just isn’t the same as cool, steady humming inside a sub. By the time F-M worked out the newly-found bugs, it was too late to keep a decent share of the locomotive market.
There are a number of companies trying to develop rotary engines for heavy duty diesel applications. I am no engineer(of either variety) but from what I’ve read problems include the fact that rotaries tend to use more fuel per KW then comparably rated piston engines (although they have a much higher power-to-weight ratio) and I think they may be emission issues with diesel fueled variants.
As far as using 4 cylinder versions of low speed marine diesels in locomotive service wouldn’t it be harder to fit them onto a locomotive frame due to bulk? I do know that some of the real monster ship powerplants are in-line, rather than V but still? I wouldl also speculate that there may be some power curve utilization differences in the 2 applications. Note that tugboats tend to use medium speed diesels much like locomotives do. In fact EMD 645 and 710 series engines are probably the most popular for tugs and other workboats, at least in North America. In both cases you are dealing with frequent throttle/RPM changes, whereas a container ship at sea runs at pretty steady RPM’s (I would imagine).
I seem to recall that one of the big problems with the rotaries was the rotating seals…they would wear faster than rings on pistons, causing decreased compression and loss of power sooner than experienced with regular piston rings…
I liked the concept of the “Effeciency” of rotary motion…is seemed it would be less vibration prone than the up/down/up/down recips…
While Mazda appears to have solved the rotor tip seal problem for automotive applications, those application are operating with a nominal compression ratio in the range of 8:1 to 10:1. Diesels, due to their compression ignition operation, tend to have compression ratios of 16:1 to 22:1. I would suspect there would be some serious engineering issues involved in getting the rotor tip seals to survive at this level of compression.
Would the stability of the engine be a factor in this at all? I would think a bigger piston in a bigger cyllender might be more prone to virations and any jostles and jolts that the locomotive encounters, although at operating speed, i’m not sure a little jolt has enough force to even effect the path the piston takes inside the engine, or if clearances are even wide enough for that to be an issue.
Also, on a slightly unrelated note, if EMD engines are so popular in tugboats and other applications, why does there seem to be a problem getting parts for older F units and the like that still use the engines? Or is it just the overall maintenance of an older locomotive that makes them unpopular, combined with poor rearward visibility?
One has to remember that there are different models of EMD engines, and most of the current marine applications use 645 or 710 engines, which still get parts support from EMD. On the other hand, I don’t believe that EMD still supports the 567 engine, which would explain why finding parts for an F7A requires some first-class scrounging.
Most early locomotive diesels were derived from marine designs, the most obvious example being the De La Vergne engine used by Baldwin with its massive cylinders and low speed (625 RPM maximum). The OP has been mentioned, and I believe that the 201-A (Winton) was originally a marine engine.