QUOTE: Originally posted by dharmon Originally posted by kenneo I mentioned before in an earlier thread that the Navy uses EMD 567s and 645s in aircraft carriers as standby generators. They use a compressed air starter, operated an electrically closed valve. If power fails, the valve opens and starts the generator. They, fortunately aren't used too much in this manner, but they are tested periodically. It never failed though, I'd be on the bridge and the engineers would call up and tell us they were going to start a diesel for maintenance........two minutes later, almost on que the bridge phones would start ringing with reports of smoke from all over the ship..... Heh! At least your engineers got the emergency diesel generators running. When I was on the old CG-10, we had an ED right below my berthing space. Whenever we'd go dead in the water, the diesel wouldn't start. Made the Chief Engineer's life very difficult, since his ENs couldn't seem to get them running. I'm no expert on Alco locomotives, but I did read that the PAs were plagued by troubles because Alco "hurried" them onto the market to compete with EMD. I don't know all the particulars, just what I had read. Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Tuesday, December 9, 2003 5:06 PM Turbos don't typically use belt, by definition they use exhaust gasses to spin up to speed. I never had the priviledge of working on the PAs, but I racked up a lot of miles on FAs, and RSs on the old SP&S, and I can assure you that a properly maintained 244 or 251 is a real workhorse. I realize that the SP&S provided exceptional maintenance for their locomotives, and this surely had an effect. I can assure you that a brace of ALCO FAs was quite capable of holding its own against the GN GP 7s we used in Oregon on the Trunk. Reply Edit adrianspeeder Member sinceMarch 2002 From: Harrisburg PA / Dover AFB DE 1,482 posts Posted by adrianspeeder on Tuesday, December 9, 2003 6:03 PM A diesel engine runs SOOOOOO much better with a turbo. My ford turbo diesel makes a heck of a lot of power. I drove a pickup with the same engine as mine, minus the turbo, and the difference is like night and day. Or dare I say a big burly ALCO against a wussy GE.[:D] I am quite proud that my three and a half tun TRUCK can beat any sports car or little import thingie off the line up to about 60mph.[}:)][}:)][}:)] Turbo diesels are where it's at![8D] Adrianspeeder USAF TSgt C-17 Aircraft Maintenance Flying Crew Chief & Flightline Avionics Craftsman Reply Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Tuesday, December 9, 2003 6:06 PM I agree with the turbo lag,and as mentioned"EMD" used blowers on theres so it already had air when throttled up. A point worth mentioning is the most obvious, the EMD's are two stroke, all Alco's are four stroke.two stroke is preassurized to purge the cylinders Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Tuesday, December 9, 2003 6:50 PM Sorry, let me clarify. Some early turbocharged diesel engines used a belt driven turbo. However most opted out for exaust driven turbos, due to the high maintainence, inefficency, and belt slippage of the earlier belt driven turbos.[;)] Reply Edit kenneo Member sinceDecember 2001 From: Upper Left Coast 1,796 posts Posted by kenneo on Wednesday, December 10, 2003 1:04 AM QUOTE: Originally posted by CSSHEGEWISCH Alco 244's & 251's and GE FDL's are all 4-cycle engines. FM OP's and EMD 567's, 645's and 710's are two-cycle engines. I'm not sure about De La Vergne (BLW) or Hamilton engines. EMD diesels, being 2-cycle, required a Roots blower to force air into the cylinders if they were not equipped with a turbocharger. A turbocharger is a good way to get extra horsepower out of a given design, but it is a high-maintenance item and this may be why EMD avoided turbochargers until Union Pacific forced the issue in the late 1950's. de la Vergne and Hamilton engines were 4 cycle Eric Reply kenneo Member sinceDecember 2001 From: Upper Left Coast 1,796 posts Posted by kenneo on Wednesday, December 10, 2003 1:25 AM QUOTE: Originally posted by 1938northern Turbos don't typically use belt, by definition they use exhaust gasses to spin up to speed. I never had the priviledge of working on the PAs, but I racked up a lot of miles on FAs, and RSs on the old SP&S, and I can assure you that a properly maintained 244 or 251 is a real workhorse. I realize that the SP&S provided exceptional maintenance for their locomotives, and this surely had an effect. I can assure you that a brace of ALCO FAs was quite capable of holding its own against the GN GP 7s we used in Oregon on the Trunk. Amen. An ALCO will outpull an EMD or GE horse for horse. A properly maintained ALCO, that is. I worked joint SPS/SP Agencies and as such am a member of the SPS Survivors. The RS3's with less HP and 2 fewer axels and 2/3 the weight would outpull an SD-9, and that is no mean feat. The SP used their 3 Alligators (2,400 HP RSD-15's) as hump engines at Eugene and it took 2 AS616's (actually, they were DRS 6-6-15's) or 2 SW15's to do the same work. If they needed to sub a locomotive for the hump, they would have to use an SD40 or 45 if they didn't have 2 SW15's. Eric Reply kenneo Member sinceDecember 2001 From: Upper Left Coast 1,796 posts Posted by kenneo on Wednesday, December 10, 2003 1:32 AM QUOTE: Originally posted by rdganthracite EMD uses a little trick to avoid turbo lag. They have the turbo set up so that it normally runs using the exhaust gasses, but if the engine is accelerating quickly there is a gear box connected at one end to the crankshaft and at the other end to a fluid coupling which spins the turbo faster than the exhaust gasses under those conditions but allows it to be driven by the exhaust otherwise. This little trick is the main reason most short lines and regionals use non-turboed 567's. That little gear box is a real maintenence hole when the locomotives are used in switching service. The Roots Blowers permit you to hear each cylinder fire, which is where the "EMD Chant" comes from. I have to admit that the most beautifully sounding engines are 567C's and 567D's. Eric Reply d4fal Member sinceOctober 2003 From: Canada 36 posts Posted by d4fal on Wednesday, December 10, 2003 6:06 AM My uncle says that the PA's burned oil and had poor seals, which did not help any. He liked it for the get up and go, but they were dirty working machines. Not the newer sleek untits that replaced them. His experience was likely tainted by comparision to other units my Uncle drove over the years. But then, the Rogers Pass was not too kind to locomotives that plied it. Reply Overmod Member sinceSeptember 2003 21,669 posts Posted by Overmod on Thursday, December 11, 2003 1:00 AM Belt drive would be a supercharger, not a turbo. "Turbo" implies exhaust-pressure turbine driving a (usually centrifugal) impeller. The General Motors crankcase blowers were positive-displacement Roots blowers (on a related note -- pun intended -- a similar arrangement was used on the GM truck diesels, which gave some of them that screaming wail... and also gave generations of dragsters their "6-71" blowers...). The Roots requires internal gears to keep its rotors precisely aligned, whether or not its input shaft is driven by belt or gear. Part of the PA unreliability problem could be attributed to its 244 engine. This had the same kind of problem seen in the big GM 20-cylinder engines: the length of the crankshaft and the engine firing order could induce torque stresses that caused failure. The FA cranks were shorter and AFAIK didn't have as much, if indeed any, increased incidence of failure. The early turbos didn't have the benefit of later metallurgy and bearing tech. These were very-large-diameter Buchli style, with truly astounding rotational inertia; spooling one of these monsters up with the exhaust, every other crank revolution per cylinder on a four-stroke, from the (as-previously-posted) slow idle rpm, was not a particularly rapid exercise. A little diesel science for anyone who may be confused: The fuel on a diesel is under direct mechanical control (via the injection system) and the amount injected determines the power the engine produces. The induction system works entirely with air. On the compression stroke, the air is (adiabatically) compressed, heating as it does so until well above 'ignition point' of the injected fuel, but kept dense by the heavy cylinder walls, piston crown, etc. When the fuel is injected, it lights off spontaneously in the hot air, and is intended to burn completely in an excess of oxygen. Remember that you get most of the compression energy back during the power stroke, in addition to the expansion due to heat-energy release from the burning fuel. Here's where things get a bit tricky. When *accelerating* the engine, you have to do the pumping work 'ahead' of the energy release from the cylinders. The only way to accelerate the engine is to burn more fuel (thereby liberating more heat) -- but if there's insufficient oxygen to burn the additional fuel cleanly, some of it will remain uncombusted... think of this as the black soot, etc., that forms the "burning-of-Rome" smoke effects. The turbocharger is ideal for a diesel because it uses residual heat expansion energy in the exhaust to compress -- and thereby make denser -- the intake air, which then has more oxygen molecules available for fuel combustion. The problem was greatly compounded on Alcos because of a characteristic of the locomotive control system. The 'correct' way to mitigate smoke would be to allow the engine to accelerate under very low generator loading, to spool the turbocharger up, and then apply generator field once the engine had come up to anticipated 'operating' rpm. Unfortunately, the integrated 'throttle' control wouldn't allow this -- in fact, IIRC it would load the main generator FIRST, and the engine governor would detect the added load as a slowing of the engine (whoops! bad idea to let a diesel slow down when you want to increase its power output!) and respond by... well, delivering more fuel, the only thing the engine control system can vary. This works, because the hydrogen in the fuel molecules ignites and burns 'first', and this will produce enough exhaust volume and pressure to kick the turbo up to boost speed. But very large amounts of the carbon 'backbone' of the fuel molecules are left unburned in this situation -- and out the stack they go! As the air delivery from the turbo reaches higher and higher levels, more and more of this carbon has sufficient oxygen to burn completely to carbon dioxide. When there is more air than fuel, the exhaust becomes essentially invisibly clear. I can also mention, from very lucky firsthand experience, that pulling the throttle quickly open on (Jersey Central) RSD units would produce the smoke effects as well. (I was four years old!) The crews used the small windows at the top on the long-hood end of the cab to see out to the stack, and that gave them some indication of how much throttle they 'should' use to accelerate their train. (Unfortunately, afaik there wasn't anything like that on the PAs or FAs -- if anyone rigged mirrors or had ways of observing the smoke while running, I'd love to hear the details! Reply Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Thursday, December 11, 2003 7:30 AM how does thta joke go what did the old alco say to the newer alco.. Your too young to smoke [:D] Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Thursday, December 11, 2003 3:17 PM Holy compression, Professor Overmod, that's quite a thorough answer to my original question! Did that experience of putting your hand to a locomotive throttle at four years old lead you to a life of diesel engineering? So the PAs just seemed like a great idea on the drawing board to the engineers, but in practial application the monster motors had some problems? Boy, if they'd just been able to engineer the inner workings as well as they engineered the aesthetics of the unit, they'd have come up with the perfect locomotive. Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Thursday, December 11, 2003 7:14 PM Ok Mr. Overmod, maybe you can answer my question. Now I have figured out the cycle for a 4-stroke diesel: 1-power stroke (down), 2-exaust stroke (up), 3-fresh air stroke (down) and 4-compression stroke (up). However I just can't get the cycle for a 2-stroke diesel, such as Winton's 201-A, or EMD's 567, 645, and 710 sreies diesels. Is the power stroke every down stroke? If so, how does the exaust get forced out, and fresh air get drawn in basically at the same time? While the fresh air is being compressed? Oh boy, now my head hurts, I'm going to go lay down. Thanks for your help with my confusion. Reply Edit kenneo Member sinceDecember 2001 From: Upper Left Coast 1,796 posts Posted by kenneo on Thursday, December 11, 2003 7:51 PM John. Simplicity itself. At the top of the cyclinder are the familure valves and injector. At the bottom of the cylinder are ports cut into the side of the cylinder wall that are uncovered by the piston at the bottom of the stroke. As the piston starts up, the valves open and force air in and the combination of the incomming air and the rising piston clense the cylinder of exhaust. The piston then passes the top of the ports and compression begins. Eric Reply CSSHEGEWISCH Member sinceMarch 2016 From: Burbank IL (near Clearing) 13,540 posts Posted by CSSHEGEWISCH on Friday, December 12, 2003 6:40 AM Further clarification on the above posting regarding two-cycle diesels. The valves at the top of the cylinder are exhaust valves only and the ports near the bottom of the cylinder are for intake air. A blower or turbocharger is absolutely necessary to force air into the cylinder since there is no vacuum effect from the movement of the piston to draw air into the cylinder. The upward stroke is a combination of intake and compression and the downward stroke combines power and exhaust. The daily commute is part of everyday life but I get two rides a day out of it. Paul Reply Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Friday, December 12, 2003 7:41 AM We used to have a song for Alcos as they went by.. I don't know if anyone knows the song "post man pat" Smokin' pat Smokin' pat smokin' pat And his black and white hat.. Reply Edit kenneo Member sinceDecember 2001 From: Upper Left Coast 1,796 posts Posted by kenneo on Friday, December 12, 2003 7:44 PM QUOTE: Originally posted by CSSHEGEWISCH Further clarification on the above posting regarding two-cycle diesels. The valves at the top of the cylinder are exhaust valves only and the ports near the bottom of the cylinder are for intake air. A blower or turbocharger is absolutely necessary to force air into the cylinder since there is no vacuum effect from the movement of the piston to draw air into the cylinder. The upward stroke is a combination of intake and compression and the downward stroke combines power and exhaust. [:I] Guess I should have been more clear. Once in a while, the exhaust valves won't open (it is rare) and the only place for the exhaust to go is out through the crankcase. Dramatic and really messy. Eric Reply Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Saturday, December 13, 2003 12:55 PM Most of the replies to this question are pretty close to the mark, the turbocharger lag is the main cause. BUT - don't forget the Model 539 engine, which was in MANY earlier Alco switchers, the RS-1, and the DL-109 road units. All would smoke heavily on acceleration - NOT all the time, as some implied. As an aside, the 539 engines were also used on a lot of Navy ships. I was Engineering Officer on one which had FOUR 539's for main propulsion (diesel-electric, just like a locomotive). Yes, they were high-maintenance engines, and when the captain said "full ahead", we always took a verbal beating about the smoke cloud! Often their exposed high-pressure fuel lines would become brittle from vibration and break at crucial times, spraying the entire engine room and crew with diesel oil. But those huge 12.5"X13" cylinders had some advantages - you could sit inside the crankcase and work on bearings, and the spare pistons made great card tables during in-port periods! Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Saturday, December 13, 2003 12:59 PM Most of the replies to this question are pretty close to the mark: the turbocharger lag is the main cause. BUT - don't forget the Model 539 engine, which was in most earlier Alco switchers, the RS-1, and the DL-109 road units. All would smoke heavily on acceleration - NOT all the time, as some implied. As an aside, the 539 engines were also used on a lot of Navy ships. I was Engineering Officer on one which had FOUR 539's for main propulsion (diesel-electric, just like a locomotive). Yes, they were high-maintenance engines, and when the captain said "full ahead", we always took a verbal beating about the smoke cloud! Often their exposed high-pressure fuel lines would become brittle from vibration and break at crucial times, spraying the entire engine room and crew with diesel oil. But those huge 12.5"X13" cylinders had some advantages - you could sit inside the crankcase and work on the bearings, and the spare pistons made great card tables during in-port periods! One more comment - PLEASE don't use apostrophes (') in the plural of "ALCO" - they are only appropriate in the possessive, as when something belongs to ALCO or an ALCO product. Thanks from an old editor. Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Saturday, December 13, 2003 1:20 PM A quick note on useage -- ALCO, ALCo, and Alco, with or without the apostrophe in the plural. For many years, Trains' style would be Alco's for both the plural and the possessive, just as it was SD40-2's for both plural and possessive. The reader had to decide which was which based on the context of the sentence. The rationale for the use of apostrophe s for the plural form was that some railroads, notably Pennsy, used a lower case s in steam locomotive classes, notably K4s (s for steamheating), and there was concern that readers would infer that any locomotive class with a lower-case s was superheated. We changed this last year because we no longer have cause to use lower case s for superheated more than perhaps once a year. We now use apostrophe s only for possessive, and just plain s for plural, which we think adds clarity. But wouldn't you know it, a lower case letter is back to haunt us, this time with EMD's new locomotive model, the SD70ACe. SD70ACes is poor, so rather than use the plural form, so we're recasting sentences to avoid the plural form and avoid this problem. We use Alco instead of ALCO or ALCo in the magazine. A quick comment on Alco locomotives. Harold Crouch, former mechanical officer at the New York Central, observed in "Keeping New York Central diesels rolling" in the January 1986 issue that for every penny NYC paid to operate its EMDs, they spent 1.5 cents for their Alcos, and 2 cents for their Baldwins and F-Ms. As he noted, you didn't have to be clairvoyant to figure out which builder NYC was going to favor. Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Saturday, December 13, 2003 3:41 PM i agree the alco PAs were good engines for there day Reply Edit kenneo Member sinceDecember 2001 From: Upper Left Coast 1,796 posts Posted by kenneo on Saturday, December 13, 2003 11:30 PM Mr. Hemphill -------- you may want to copy your last paragraph to the SD80 thread. It applies there also. Eric Reply Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Thursday, September 7, 2006 11:42 AM When I was in the navy on an Newport class LST (the USS Saginaw, LST1188, I was an enginman) our ship had ALCO's (16-251's for mains, 8-251 for genorators). Those engines were natural oil burners (manuals said so) because the cyl walls had tiny dimples in them. Some other Newport class LST's had some type of GM. They had a hybrid blower / turbo. At lower speeds it was a blower, at higherspeeds it unclutched from the engine and became a turbo. However, navy is constantly training while under way, so they constantly change speed. This caused the clutches to have a high failure rate so the ALCO's were a lot more reliable. Just before transfering off te Saginaw we herd they were experimenting with eliminating the cluch. The GM's are 2 strokes without crank case scavaging ( all GM diesels with the exception of light and medium duty ones are) so they must have a blower at low speeds until they have enough exaust preasure to spin the turbo. The alco is a 4 stroke so the turbo is only for power boost and it runs without it at low speeds. Another sorce of smoke on ALCO's is crank case scavaging. Instead of sucking crank case fumes into the engine to be burned as most engines do (there was a lot of it due to those dimples) they used an scavaging ejector powered by air presure from the blower to blow it out another exaust. These were a sorce of much grief for us since the simply discharged into the engine room exaust and put lots of oil in them, causing a fire on one of the LST's Reply Edit Leon Silverman Member sinceJuly 2004 785 posts Posted by Leon Silverman on Thursday, September 7, 2006 2:09 PM Clayr wrote"... At lower speeds it was a blower, at higherspeeds it unclutched from the engine and became a turbo. However, navy is constantly training while under way, so they constantly change speed. This caused the clutches to have a high failure rate so the ALCO's were a lot more reliable. Clayr: I am surprised that these engines went through large speed variations. These LST's had variable pitch propellers that permitted propulsion by one, two, or three engines per shaft. This may have been the difference between design parameters and operational parameters. Reply Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Friday, September 8, 2006 8:15 AM Not large speed changes. I think idel was around 500. top end was 900 for the alcos. I don't know abouth the GM's. All boats with VPP have some variance in engine rpm. An engine running full speed lightly loaded isn't as fuel eficient. They would raise rpm and pitch simotaniously. For some reason they never used full auto mode but set rpm and pitch manually. Aso, you wouldn't want it to idel at 900. At 500 (asuming that's th idel for the GM's) you wouldn't have the exaust flow to turn the blower, so it's engine drivenat those speeds. Trains (except for switching engines) and civilian ships would natually set a speed and hold it as much as posable to save fuel so you wouldn't constntly clutchand unclutch. Reply Edit Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Saturday, September 9, 2006 1:16 AM Thanks to Clayr, I just remembered a huge standby generator in a steam ship's engine room that had "ALCO" cast into its sides. I have no idea what the model# of this engine was. The ship was mid-70's vintage. Did ALCO (the locomotive company) make diesel engines into the 1970's? Reply Edit CSSHEGEWISCH Member sinceMarch 2016 From: Burbank IL (near Clearing) 13,540 posts Posted by CSSHEGEWISCH on Saturday, September 9, 2006 6:45 AM Alco in Schenectady got out of the locomotive business in 1969 but did continue to market its engines for marine and stationary use for some years afterward. The daily commute is part of everyday life but I get two rides a day out of it. Paul Reply Anonymous Member sinceApril 2003 305,205 posts Posted by Anonymous on Saturday, September 9, 2006 7:14 AM Compared to the steam engines they were replacing, they hardly smoked at all The September 2001 issue of Trains had an excellent series of articles on the 100 year history of Alco and what went wrong with the early diesels. Well worth finding if you're an Alco fan and don't have it. One advantage they did have over early EMD's was the GE supplied traction motors and electrical gear, which was more reliable. The problems with the Alco prime movers, caused GE to start building locos in house. Reply Edit 123 Join our Community! Our community is FREE to join. To participate you must either login or register for an account. Login » Register » Search the Community Newsletter Sign-Up By signing up you may also receive occasional reader surveys and special offers from Trains magazine.Please view our privacy policy More great sites from Kalmbach Media Terms Of Use | Privacy Policy | Copyright Policy
Originally posted by kenneo I mentioned before in an earlier thread that the Navy uses EMD 567s and 645s in aircraft carriers as standby generators. They use a compressed air starter, operated an electrically closed valve. If power fails, the valve opens and starts the generator. They, fortunately aren't used too much in this manner, but they are tested periodically. It never failed though, I'd be on the bridge and the engineers would call up and tell us they were going to start a diesel for maintenance........two minutes later, almost on que the bridge phones would start ringing with reports of smoke from all over the ship.....
USAF TSgt C-17 Aircraft Maintenance Flying Crew Chief & Flightline Avionics Craftsman
QUOTE: Originally posted by CSSHEGEWISCH Alco 244's & 251's and GE FDL's are all 4-cycle engines. FM OP's and EMD 567's, 645's and 710's are two-cycle engines. I'm not sure about De La Vergne (BLW) or Hamilton engines. EMD diesels, being 2-cycle, required a Roots blower to force air into the cylinders if they were not equipped with a turbocharger. A turbocharger is a good way to get extra horsepower out of a given design, but it is a high-maintenance item and this may be why EMD avoided turbochargers until Union Pacific forced the issue in the late 1950's.
QUOTE: Originally posted by 1938northern Turbos don't typically use belt, by definition they use exhaust gasses to spin up to speed. I never had the priviledge of working on the PAs, but I racked up a lot of miles on FAs, and RSs on the old SP&S, and I can assure you that a properly maintained 244 or 251 is a real workhorse. I realize that the SP&S provided exceptional maintenance for their locomotives, and this surely had an effect. I can assure you that a brace of ALCO FAs was quite capable of holding its own against the GN GP 7s we used in Oregon on the Trunk.
QUOTE: Originally posted by rdganthracite EMD uses a little trick to avoid turbo lag. They have the turbo set up so that it normally runs using the exhaust gasses, but if the engine is accelerating quickly there is a gear box connected at one end to the crankshaft and at the other end to a fluid coupling which spins the turbo faster than the exhaust gasses under those conditions but allows it to be driven by the exhaust otherwise.
QUOTE: Originally posted by CSSHEGEWISCH Further clarification on the above posting regarding two-cycle diesels. The valves at the top of the cylinder are exhaust valves only and the ports near the bottom of the cylinder are for intake air. A blower or turbocharger is absolutely necessary to force air into the cylinder since there is no vacuum effect from the movement of the piston to draw air into the cylinder. The upward stroke is a combination of intake and compression and the downward stroke combines power and exhaust.
Clayr wrote"...
At lower speeds it was a blower, at higherspeeds it unclutched from the engine and became a turbo. However, navy is constantly training while under way, so they constantly change speed. This caused the clutches to have a high failure rate so the ALCO's were a lot more reliable.
Clayr:
I am surprised that these engines went through large speed variations. These LST's had variable pitch propellers that permitted propulsion by one, two, or three engines per shaft. This may have been the difference between design parameters and operational parameters.
Not large speed changes. I think idel was around 500. top end was 900 for the alcos. I don't know abouth the GM's. All boats with VPP have some variance in engine rpm. An engine running full speed lightly loaded isn't as fuel eficient. They would raise rpm and pitch simotaniously. For some reason they never used full auto mode but set rpm and pitch manually. Aso, you wouldn't want it to idel at 900. At 500 (asuming that's th idel for the GM's) you wouldn't have the exaust flow to turn the blower, so it's engine drivenat those speeds. Trains (except for switching engines) and civilian ships would natually set a speed and hold it as much as posable to save fuel so you wouldn't constntly clutchand unclutch.
Compared to the steam engines they were replacing, they hardly smoked at all
The September 2001 issue of Trains had an excellent series of articles on the 100 year history of Alco and what went wrong with the early diesels. Well worth finding if you're an Alco fan and don't have it. One advantage they did have over early EMD's was the GE supplied traction motors and electrical gear, which was more reliable. The problems with the Alco prime movers, caused GE to start building locos in house.
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