Re: Pusher Service

is there not a steep hill on the UP between Rochelle and Chicago..
but that would be empty trains going west that have the battle right??
Clare
Reply to
allenby
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According to my brother who is an engineer - DP makes it harder to keep a train in one piece. Just when you want to strectch it out the tail end is bunching it up and vice versa. The engineers hate them.
Dale.
Steve Hosk> On 11 Aug 2003 01:07:45 GMT, snipped-for-privacy@aol.com (CBT2000) wrote : >
Reply to
Dale Gloer
"Steve Hoskins"
Actually no, coal isn't heavy. It's quite light. It'll even float. However, the freight cars do carry at lot of it and that makes the load heavy.
-- Cheers Roger T.
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of the Great Eastern Railway
Reply to
Roger T.
But when you have 100 tons of something -- be it coal or feathers -- in each car, the train gets heavy no matter what.
Reply to
Steve Hoskins
"Steve Hoskins" <
That's what I said.
-- Cheers Roger T.
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of the Great Eastern Railway
Reply to
Roger T.
Precisely. Coal trains max out on weight. Coal hoppers don't often move with less than rated load (unless empty of course). That's not true of many other commodities that may 'bulk' out (fill the car) long before maximum weight is reached.
Most cars today have capacities on the order of 100 tons (70 tons in W.W.-II days). That's approximate. That's the most that can be carried on eight (freight car sized) wheels. Approx. 25 tons per axle, 12.5 tons per wheel. The problem lies with the rail, not the wheels. Exceed the 25 tons per axle and you permanently deform the rail. A LITTLE of this can be tolerated (as with locos), but if all the cars in the train exceed this limit, the rail is rapidly destroyed. Attempts to run 125 ton cars have made this problem quite obvious. Bigger wheels can carry more weight without damaging the rail, hence the tendency towards 36" and even 38" wheels on some equipment.
Similarly, six axle cars can carry on the order of 150 tons. The extra upkeep cost on the more complicated trucks, and tracking problems, limits their use. Similarly for four (or more) truck cars. They're used where they're NEEDED, but not in mass numbers.
To use the example previously stated: A loose feather car would have to be positively HUGE to contain 100 tons of such feathers. Far bigger than a Hi-Cube boxcar. Clearances prevent such a monster, so bulk feather cars [ *IF* any :-) ] run at WAY below the 100 ton limit. They 'bulk out' long before they reach maximum weight. Much mixed freight does this as well.
Plus mixed commodity trains will usually have a mix of loaded and empty cars. Bulk transport cars will often run in sets (sometimes unit trains), and will be either all full, or all empty. We're not considering the 'empty' case here.
And, a railroad may add more cars to a train if the cars are lighter, but there are limits on siding length, etc. that limit this practice. Such trains will not usually max-out on weight ... something else will limit train size.
SO, loaded coal, ore, and similar trains are, on the average, heavier than loaded mixed commodity trains.
Dan Mitchell ==========
Steve Hosk>
Reply to
Daniel A. Mitchell
Agreed. But the original poster stated that coal is heavy, which it isn't. :-)
-- Cheers Roger T.
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of the Great Eastern Railway
Reply to
Roger T.
Try humping a wagon load by the sack-full, around about sack number 20 it's heavy!
Reply to
Gregory Procter
"Gregory Procter" <
Shovelling seven tons in a 10 hours shift into a firebox. Been there, done there, got the T-Shirt.
You can do that because each shovel full doesn't weigh that much.
-- Cheers Roger T.
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of the Great Eastern Railway
Reply to
Roger T.
The car adapts itself to the volume of the load - where's the problem?
Greg.P.
Reply to
Gregory Procter
Agreed, but compared to what? For a given volume, coal is light compared to iron ore and heavy compare to feathers.
Look at cars designed to haul a particular commodity. If the car is large, the commodity has low (weight) density. Such cars often 'bulk out' before they reach their weight limit. If the car is small, the commodity has high density. such cars (loaded) will usually be AT their weight limit. That's why ore cars are so much smaller than high-cube boxcars ... they both have about the same weight limit, something like 70 -100 tons.
Coal hoppers are sometimes used to haul iron ore ... they just can't be filled only about half full or the car goes overweight. Seen from the ground they look like 'empties', but look at the truck springs and you can tell they're loaded to (weight) capacity.
Dan Mitchell ==========
"Roger T." wrote: > > > SO, loaded coal, ore, and similar trains are, on the average, heavier > > than loaded mixed commodity trains. > > Agreed. But the original poster stated that coal is heavy, which it isn't. > :-) > > -- > Cheers > Roger T. > >
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Home of the Great Eastern Railway
Reply to
Daniel A. Mitchell
None if the car is made of rubber.
Andy -----------------------------------------------------------
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- Pre-Interstate Urban Archaeology -----------------------------------------------------------
Reply to
Andy Harman

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