Thanks to Chris / CopCarSS for my avatar.
QUOTE: Originally posted by Murphy Siding I've mentioned that steam locomotives didn't do much for me,but I have been doing quite a bit of railroad reading recently-so they might grow on me.[:)] In the steam era, it appeared that nearly every railroad had almost custom designed engines, specifically for it's route. I'm familiar with some of the more famous ones:Big Boy, Challenger,Berkshire,J-1(? N&W), and a few others. What are some of the other well known types that other railroads had? And can you explain to this *diesel* fan what the signifigance of the type was? I still have a hard time seeing the difference between two similar types. Thanks!
QUOTE: Originally posted by Murphy Siding bobwilcox: Thanks. I read the article on the link. It's not really clear why the AMC designed Berkshire was better than the Lima or Alco Berkshires. Perhaps just a better engineered design? The article talks about the jump from 2-8-2 wheel layout to 2-8-4 as providing more carrying capacity for a bigger firebox. What would be the advantage of the 4 wheel leading trucks on some later designs?
QUOTE: Originally posted by bobwilcox QUOTE: Originally posted by Murphy Siding bobwilcox: Thanks. I read the article on the link. It's not really clear why the AMC designed Berkshire was better than the Lima or Alco Berkshires. Perhaps just a better engineered design? The article talks about the jump from 2-8-2 wheel layout to 2-8-4 as providing more carrying capacity for a bigger firebox. What would be the advantage of the 4 wheel leading trucks on some later designs? A bigger firebox. The larger the grate area the more fuel you can burn at one time, the more heat and the more steam. The grate area on a USRA 2-8-2 was 70.8 sq ft., a B&A 2-8-4 100 sq ft and a UP Big Boy 150.3 sq ft.
QUOTE: Originally posted by Old Timer Murphy Siding - the four-wheel trailer was necessary to carry the weight of the larger firebox. C&O and NKP fans will tell you that the AMC Berkshires were better, but they're prejudiced. There were two sizes of the AMC Berks - the C&O was larger (one inch larger cylinders, etc.) and the NKP was smaller. But neither was as pretty as the L&N Berk, which was a match for the smaller AMC. Old Timer
QUOTE: Originally posted by Lotus098 Get your self a good book like mine. "The Steam Locomotive A Century of North American Classics" by Jim Boyd. If this doesn't get you interested in steam, nothing will.
QUOTE: Originally posted by Wdlgln005 You may be starting a bit of a flame war between similar locos on different railroads. No 2 steamers were exactly the same, unlike diesels. some versions could be good steamers, others unlucky or junk. Since they were custom built, a lot depends on the operating character of each RR. It becomes fun to try to compare J class Northerns on N&W with those on UP or any other RR. The 4 wheel pilot truck was developed fairly early for the steamer to be guided over poorly built track. 2 wheel trucks were used for slow moving freight. Driving wheel diamaters determined speed. Large 60" drivers could easily move the engine at 60 per hour, Smaller ones gave more traction & HP or drawbar pull. Adhesion is the factor that determines how much HP is available to pull a train. The class number like J, depends on the railroad. Some roads gave the little teakettles A's, the next one B's etc. A J3 would be the third group of locos purchased. Chances are, lessons learned will result in improved locomotives with different valve gear, stokers, & other changes. You would get a huge argument over who had the best Northerns. In the South, they would be called Dixies or Yellowjackets. The Yellowjacket name comes from the yellow painted stripe on the running board edge & tender of locos. The best stories should come from the engineers that operated & controlled all this machinery. No computers. Not many automatic appliances. Hot in the summer. Cold in the winter, except for the heat provided from the firebox. Yet, the enginemen operated these machines for over a century in all kinds of conditions. Crews on the FEC tried to outrun the hurricane that destroyed the RR. Today, Amtrak was unable to run trains near the zone till the storm passed.
QUOTE: Originally posted by Old Timer Murphy Siding - the four-wheel trailer was necessary to carry the weight of the larger firebox.
QUOTE: Originally posted by futuremodal QUOTE: Originally posted by Old Timer Murphy Siding - the four-wheel trailer was necessary to carry the weight of the larger firebox. This brings to mind a question left unanswered on the T1 thread. Remember the 4-6-0 locomotives? They had a "gap" between the second and third set of drivers to support the firebox. I have assumed that since larger fireboxes required more width than could be afforded between 4' 8.5" gauge, they had to abandon the idea of supporting the firebox with the drivers and relegate that requirement to a supporting truck under the firebox. The question I had is this: Why couldn't the drivers support a wider firebox by extending outward the connecting rods between the driving axle in front of the firebox and the driving axle behind the firebox? That way you have more weight being supported by the drivers (e.g. more traction) instead of a non-driving trailing truck, while still maintaining the advantage of the larger firebox.
QUOTE: Originally posted by futuremodal The side rods are(were) connected on the outside and next to the driving wheels (which are 4' 8 1/2" apart widthwise, give or take material dimensions), so the rods on opposite sides of each other are(were) about 5 - 5 1/2'(?) apart in width. The larger fireboxes were made to maximize the allowable width of a locomotive 10', maybe 10 1/2' wide. So you couldn't have the typical side rods compatable with the wider fireboxes as was done with the 4-6-0 locomotives. But if you could somehow extend outward the connection between the rod and driver wheel by a foot or so, you could conceivably fit a firebox with a 9' or so width between such outwardly extended rods between a front set of drivers and a rear set, and support this firebox between such driver wheels. I do not know if this is technecally feasable, but I see no reason why it wouldn't work as intended.
QUOTE: Originally posted by Murphy Siding QUOTE: Originally posted by futuremodal The side rods are(were) connected on the outside and next to the driving wheels (which are 4' 8 1/2" apart widthwise, give or take material dimensions), so the rods on opposite sides of each other are(were) about 5 - 5 1/2'(?) apart in width. The larger fireboxes were made to maximize the allowable width of a locomotive 10', maybe 10 1/2' wide. So you couldn't have the typical side rods compatable with the wider fireboxes as was done with the 4-6-0 locomotives. But if you could somehow extend outward the connection between the rod and driver wheel by a foot or so, you could conceivably fit a firebox with a 9' or so width between such outwardly extended rods between a front set of drivers and a rear set, and support this firebox between such driver wheels. I do not know if this is technecally feasable, but I see no reason why it wouldn't work as intended. My guess is that you'd be making the engine wider-maybe too wide for some clearance situations like tunnels?
QUOTE: Originally posted by Murphy Siding I did a bunch of reading on this subject today. However I'm thinking that you're a little dimensionally challenged on this: The driver wheels are 4'-8" apart. The side rods are connected to the outter face of the drivers, at the outside radius. Height wise, the rods are a little taller off the ground than the drivers. No matter how you offset the connecting rods outward, the dimension between the drivers will remain about 4'-8". The *old* steamers had the fire box between the drivers- therefore less than 4'-8" wide. The *newer* designs looked like the firebox was moved back, behind the drivers and no longer resrained to 4'-8" dimensional width. To carry the firebox weight, it looks like either 2 or 4 trailing wheels were added.
QUOTE: Originally posted by GN-Rick A large problem with the concept of the 'extended rods' concept would be a very serious increase in dynamic augment-the inertia of extra mass reciprocating around the axles. It seems to me that you would have a very rough-riding locomotive that would be almost impossible to properly counterbalance-thereby increasing wear on bearings and bushings. After all, counterbalancing even the locos that existed was one of the more difficult tasks given to mechanical departments and locomotive designers. A notable steam loco, in my opinion is the class N3 2-8-8-0 as rebuilt by the GN in 1940-42. An articulated loco with 63 inch drivers, no trailing truck and only a two wheeled lead truck that was capable of running with heavy loads at 50-60 mph. And with an 118,000 lb tractive effort. Impressive-yet undernoticed.
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