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[AC6000CW]

does any body know all of the diesel locomtives maxim rpm's that they can make it up to.

[Anonymous]

Gosh... i dont think much higher than 800 rpm? I dunno im not an engineer.

[Anonymous]

For trucking slow rpm is good. Some desiels are just too puny to provide the performance desired. On I-70 West near Breezewood at a grade called "Town Hill" which is a 4 mile hill; I have two trucks with two different engines for the same load.

Mack CH model 350 engine, shorter gearing on the transmission provides about 1200 RPM at 44 mph under 77,000 pounds gross weight to run the hill.

Older Cummins Big CAM IV 350 with tall gears probably needs 1800 RPM for 23 mph (Give or take a little depending on season) to run the same hill.

The Mack will get to the top first. This was why I asked for the newer Mack when my flatbed company in Maryland made them availible. It was able to get over the hill faster because on time delivery in Altoona was pretty important. However the Freightliner with the 350 Big Cam probably did much better on the Tidewater in east VA and eastern shore of maryland.

Now if you put a current model 600 CAT on that truck with a Rockwell or EATON I expect that truck to probably run that grade somewhere above 50 mph. Take that same CAT to the tidewater and it will literally "Sleep" with hardly any effort on the flatlands. And when it is time to run Emigrant or Donner out west.. you would have the best engine for the task. The other two engines I talked about would just simply burn up and burn all your fuel and take too long on these big western hills.

The difference between desiels and gasoline is torque. Gas runs out at the top end and gives you all kinds of giddy-up go but does not have the brawn to lug heavy loads up hill.

Desiels are pretty slow at getting to top end.. But when you are somewhere between torque and high horsepower on the tachometer you are going to find yourself with a engine that has brawn plenty for the job at hand.

The best test of a desiel is to do the required work with the least amount of RPM and fuel expenditure.

Pre computer days had desiels rated for 2300 RPM (Have had them at 3000+ but that story I save for another day) with high horsepower around 1900-2100 and max pull somewhere about 1500

Today's desiels probably can give you 1850 max RPM (Horsepower 1600) and max pull between 1250-900 RPM on a descending curve. Idle is about 600 with most engines like to run 1000 idle.

Some trucking companies install governors to rob the engine at a set RPM of fuel so the driver cannot speed or engage in pulling contests. I have had rigs that were carefully set at a RPM just under high horsepower and too close to high torque and you literally could not drive em. Shift down and max out, shift up and stall UGH!!!

Marine desiels probably are more concerned with fuel burn per hour versus speed of the boat or ship in knots for best economy.

Railroads want to feed traction motors with thier engines so I would imagine the focus will be on generating electricity at the required power more than sheer grunt and brawn.

[Anonymous]

Your BIG diesels are run pretty slowly. Even with the slow speed the cylinder wall piston velocity is still what you see in your car enginge when it's screaming, you just have a LOT of stroke to cover in each revolution.

Our power plant based engines have speeds between 375 RPM and 450 RPM, with outputs between 1,000 kW and 7,200 kW.

Mark in Utah

[Anonymous]

Certainly this fits with my experience of diesel power in normal cars (as opposed to trucks) - peak power tends to be between about 1800RPM and 3000RPM (where the turbo is spinning) though you can get useful torque lower down depending on the engine - after fitting a free-flow exhaust system to my diesel Land Rover It will now pull smoothly from 30mph in 5th on the flat (not going to break any speed records but it will pull it). This is from about 1000RPM. Idle speed is about 500-800 RPM. This unit won't rev much past 3000RPM and you don't want to be revving that hard anyway - the peak power is between 1500 and 2500 RPM.

[CSSHEGEWISCH]

Railroad and marine diesels (they are in the same size range) generally top out at about 1000-1100 RPM. This would be with 9" X 10.5" bore and stroke. Baldwin's De La Vergne engine was 12.75" X 15.75" and maxed at 625 RPM. In the other direction, the Maybach engines used in the D&RGW/SP diesel-hydraulics were 7.7" X 7.9" and had a top speed of 1585 RPM.

[Anonymous]

About a year ago, I had a conversation with a fellow who works in a BNSF shop up in Minnesota. He said he walked into the engine rebuild shop as they were running a newly rebuilt engine. He said he thought it was screaming and about to come out of its moorings. He looked at the tachometer and it was turning about 925 rpm.

[joseph2]

For locomotives built in the 1970's the EMD 645E engine had a maximum of 900 r.p.m. while the GE FDL-16 was designed for a max of 1000 r.p.m. This is from the book The Diesel Spotter's Guide .