U.P bigboys/challengers


bnsf971 said:
I remember one reason was the H8 had some solid bearings instead of roller bearings, and retrofitting them would have been $$$. .
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since they were built well into the rollerbearing era , why did they use something that was outdated on such a big beast ??
 
That's a good question! I too noticed fiction bearings on the tender and lead and trailing trucks of the H8 maybe because it was going to be mainly hauling coal trains and
they just felt roller bearings weren't needed on all wheels.
I have 'Allegheny Limas finest' will see if I can find a reason behind this decision.
 
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I happened to notice today while at the doctors office in a micro mark catalog i had with me that Rivarossi/Hornby is going to be releasing a sound equipped bigboy soon.....or is this old news I just hadn't noticed.MM is taking preorders $449
 
Here's another articulated that I was lucky enough to have ridden in the cab of while on their last duties as helpers over Bozeman Pass in Montana before they were scrapped. They were not high speed locomotives like the Big Boys or Challengers, but they were sure had lot of grunt. I have an older brass model of this locomotive that I use for my "traveling locomotive", which is the only DCC and sound equipped locomotive I have. Unfortunately, in normal operation, it would not have appeared on my layout as my turntables are only 90 footers. I'll take it out once and a while to keep things lubricated and run it for a bit.

np5005.jpg
 
With all the discussion about articulated's, lemme drop my 2 cents......

BB and Challengers were "OK" designs but had different parts front to back engines, so maintenance was more costly(parts availability) N&W took the USRA 2-8-8-2 and improved the exhaust porting in their Y5 series, which allowed them to get out to 55-60 mph, while still being able to start in simple, providing 152K tractive effort. while not "High Speed" they were optimzed to the grades and curve on the N&W. This was NOT done with the C&O H8's. They also developed the "A" class 2-6-6-4 earlier than the C&O H8's and even though they had slightly larger drivers (67" vs 70") the increased bioler pressure gave them a slightly higher TE than the H8's. Factor of adhesion was higher for the H8's due to their higher axle loading and smaller drivers (4.10 vs 3.78). By 1952, N&W had added 16 tons of lead onto the front engine frame to combat slipping due to better valve timing and the addition of the booster valve. Those Y6b's could generate 170K lbs TE at 6 mph. They were still able to get out to about 60mph on the flatter areas. The "A" class could get up to 100mph on the flatlands, like the "J" class passenger loco's. C&O's H8's might have been improved by increasing boiler pressure to 300lbs but they were already using them wrong for most of their service life as drag locos. It wasn't until 1948 and later that they realized the H8's could pull enormous trains at 65 mph.
 
The N&W Mallets pounded the rails at speeds above 40 mph, and so they were restricted by the management to slower drag speeds. Fortunately for alcon, that worked out the best. Any time you have massive reciprocating and eccentric weights circling small drivers, which the Y's had, where there is so little counterbalancing mass able to be applied effectively in the smaller circumference, you get high dynamic loading on the rails which literally pulverizes the ballast (not a good thing), splits ties, and bends the rails...also not good things.
 
Not true. The only engine that had problems with counter balancing was the K3 4-8-2's, which had their main siderod connected to driver #3 instead of #2 for more starting TE. They pounded the rails as driver #3 hopped above 38mph and it was those engines that were restricted to 35mph. The Y class drag engines were mostly used in areas where 20-35 mph was the speed limit. They only time they went faster is when working with an A class engine.

The Y5's and Y6's had 58" drivers and more counter weight, but it was the Y2 - Y4 series that were unable to get past 40mph due to the bottleneck in their front engine exhaust porting/piping.
 
We can disagree. I believe the Y6's had 57" drivers. I have read many threads on the subject of articulated steamers around the www, and the consensus is that the drag engines were best at drag speeds for a number of reasons, including dynamic augment due to their counterbalancing problems associated with the longer cranks relative to their smaller tire diameters and their associated wheel mass, the hunting of the hinged front end engine holding the massive LP cylinders, but also that they simply ran out of lungs/steam at speeds above 45 mph or so with the reverser set forward and the throttle pulled well back.

The Y's and A's could accompany each other down grades at the end of a pushing shift at speed where horsepower was not being applied, but when it came to speeds above 45 mph, that's what the company designed and built the A Class to do.
 
As a member of the N&W Historical Society, I contacted several locomotive historians about your info. N&W NEVER restricted Y class engine speeds. They did drag service because they were the best at it. Y5's and later did have 58 inch drivers. They were well designed and did NOT pound the rails, probably due to excellent design and maintenance. At 300 lbs boiler pressure they didn't run out of steam either.
 
This is an interesting discussion where the various posters are trying to settle on the 'best articulated' steamer. One of the posters who knows steam exceptionally well is 'overmod' who has an interesting post on the seventh page where he states that the Y6 needed better balancing if it were to be used on excursion service. By that he means that its augment begins to cause track problems, as I suggested.

http://cs.trains.com/trn/f/740/t/214464.aspx?sort=ASC&pi332=7
 
Selector said:
This is an interesting discussion where the various posters are trying to settle on the 'best articulated' steamer. One of the posters who knows steam exceptionally well is 'overmod' who has an interesting post on the seventh page where he states that the Y6 needed better balancing if it were to be used on excursion service. By that he means that its augment begins to cause track problems, as I suggested.

http://cs.trains.com/trn/f/740/t/214464.aspx?sort=ASC&pi332=7
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Crandell, I'm still reading through that thread, but in this day and age of instant information access, some people still can't be bothered by taking a couple of seconds to check their facts. The speed restriction NS placed on steam engines on their system was 40, not 45 mph. 45 was the speed restriction placed on 4501 by the Southern. That was just the first thing I saw in a couple of minutes' reading (not your post, either).
 
Apples and oranges. Are we talking TODAY, or are we discussing the steam era? the speed restrictions were on PASSENGER trains pulled by steam, not when NS was moving steam from city to city during excursion service.
 
Y3a said:
Apples and oranges. Are we talking TODAY, or are we discussing the steam era? the speed restrictions were on PASSENGER trains pulled by steam, not when NS was moving steam from city to city during excursion service.
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I know the N&W A engines were more than capable of going passenger train speeds back in the day. The Y 5 and Y6 would also easily travel at the freight speeds of the day.
In the early 1990's I remember the 611 being delayed, and hearing the dispatcher asking over the radio if they were going to be on time getting back to the point of departure for the excursion. The response was classically understated: "Yes, over". The dispatcher then asked how fast they were going. "Seven nine, over".
 
Selector said:
The N&W Mallets pounded the rails at speeds above 40 mph, and so they were restricted by the management to slower drag speeds. Fortunately for alcon, that worked out the best. Any time you have massive reciprocating and eccentric weights circling small drivers, which the Y's had, where there is so little counterbalancing mass able to be applied effectively in the smaller circumference, you get high dynamic loading on the rails which literally pulverizes the ballast (not a good thing), splits ties, and bends the rails...also not good things.
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Crandell,
I really think you need to do your homework better. Exactly where did you read that management restricted the Y's to speeds slower than 40 mph? It surely wasn't in an Employee Timetable. Before you go pontificating about something you obviously know nothing about, try reading "N&W Giant of Steam" by Bud Jeffries or "The A: Norfolk & Western's Mercedes of Steam" by Ed King or "The World's Greatest Steam Locomotives" by Eugene Huddleston. There are also numerous videos to watch and sound CD's to be heard that will also serve to educate you on the ways of the Y6.

After the 611 derailed in the Dismal Swamp in excursion service, NS decreed that all steam locomotives were restricted to 40mph.
 
We're talking about freight steam using the Y class of Mallet during the transition era, so that rules out the Norfolk Southern; it was never part of the conversation. The Y's COULD run at about 60 mph, but not developing any useful horsepower, and not without causing their crews to get very wide-eyed. Someone besides overmod in that thread said so using quotes from someone who supposedly was intimately familiar with how the Y's ran at speed.

My bad for using the term "restricted to". I ought to have said simply that they developed all their useful tractive effort and hp by the time they reached 40 mph, which is a fact.

I have seen hours of film footage taken in the Blue Ridge of both Y's and A's doing what they did, both up and down grade. I never saw a Y doing more than 40 mph down grade returning to pusher service from the top of a hill. In any event, if they went considerably faster, it wasn't developing hp in pusher service, it was returning light to the bottom of the hill. Ergo, not much hunting and not so much dynamic augment.
 
Though now very familiar with the NS, I was viewing some great video of the eastern articulateds not long ago, here's the link. http://www.youtube.com/watch?v=orHxa-ECaHA In the first half there are some great scenes of the N & W and other railroads.

I see a bit of rock throwing going on here. One thing we have to remember is that things were a lot different in the steam era. Some locomotives were built to the USRA standards, but some locomotives were developed for the particular needs of a railroad. One for instance, was the NP Z-5 Yellowstone, build for the Mandan Division, which prior to the Yellowstone, the NP had to double head, or triple head mikes to get the job done. When I was a kid, I actually rode in the cab of these giants when they were used for helper service over Bozeman Pass prior to being scrapped. They were designed to burn the low grade Rosebud coal that was readily available along the route. The fire box in this locomotive was enormous. You could hold a dance in it. The SP used the same wheel configuration for its cab forwards. Look at the Big Boy designed for the long freight trains and grades across Wyoming. In the east we have railroads like the NS that had to pull long coal train over the mountains, needing two to three locomotives to do the job. Many of these specially developed locomotives turned out to be a flop, but many performed so well, that they were later adopted by other railroads if it fit their needs. Large drivers for speed, small drivers for more pulling power. Todays diesels makes things so much simpler than back in the days of steam.

Here's another interesting video of the Norfolk & Western and Norfolk Southern. http://www.youtube.com/watch?v=fm2VZ-YXGnk

Enjoy the video.
 
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A few notes on that video;
The backwards pusher: had pushed an eastbound train over the hill, now, it is pushing a westbound train back over the same hill.
Did you notice the super elevation in some of those curves.
Some locos lifting the safety valves, no lack of steam there!
All of the sand laid down on the eastbound uphill track.
The tender rocking on the K2a's.
 
Hollins Station said:
A few notes on that video;
The backwards pusher: had pushed an eastbound train over the hill, now, it is pushing a westbound train back over the same hill.
Did you notice the super elevation in some of those curves.
Some locos lifting the safety valves, no lack of steam there!
All of the sand laid down on the eastbound uphill track.
The tender rocking on the K2a's.
Click to expand...

I was really impressed with some of the shots. That's was railroading. Growing up in the west, I am not as familiar with eastern roads, but they sure had some great heavy haulers.
 
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