When say a loaded coal train is a 9000 ton, does that mean the train weights 9000 tons or means it takes 9000 tons of force to get it rolling. My mind isn’t working[banghead]
When I worked on the railroad the 9000 tons was the train’s weight.You need to know the weight for train braking.The power desk also needed to know in order to assign enough locomotives.
That makes sence.
THANKS
There is the inertial mass of the train, and that comprises all the rolling stock plus any 'content’s…water in a boiler, lubes, fuel of any kind, and it also includes passengers and any lading or baggage.
With friction and other types of rolling resistance, about as low as you can get when it comes to steel on steel, it really doesn’t take much to get it moving if you are on level ground. A few horsepower can get a loaded coal hopper underway. Used to be demonstrated that two or three women in high heels could tug or push a Northern 4-8-4 with Timken roller bearings if it were a well-balanced design and build. So, maybe 3 HP if they were working hard and not in danger of breaking their spiked heels? And that’s for a 200 ton locomotive, and another 180 tons or more for a large tender.
To get 9000 tons to move, and then to accelerate it, you need both HP and tractive effort. A locomotive weighing 230 tons can generate over 100,000 lbs of tractive effort and get a heavy train moving all by itself in the right conditions. The weight of the locomotive and the adhesion of its steel tires on the smooth steel rails have to be such that the tires retain their purchase on the rails and don’t slip. It may be a slow acceleration, but it will happen…all 9000 tons.
Add a grade, though, and all bets are off. For every 0.5% of grade you make the locomotive lift the train, you will have to make the locomotive generate about three times (X3) as much HP as it took to move the train over level track. Important point: this is when the train is underway, already in motion. If you have a single locomotive hauling 9000 tons on level track @ 20 mph, it will take approximately three times the HP to sustain that speed up a 0.5% grade.
As the grade gets steeper, the tractive effort of the diesel could become insufficient to keep its wheels from slipping. That is the point where you would want t
A engineer would turn on the sanders and add throttle as needed and the power desk would be sure there is enough horse power/TE to get the job unless a set of helpers will be added en route to help boost the train upgrade.Also down hill braking would be factored in so the PD would ensure all bases are covered that’s their job.
Here’s the way we did it.
The out going crew would look at the tonnage, number of cars in the train consist and note any hazmat cars,number of locomotives in the locomotive consist and note the lead unit number and the outbound track number the train was on…Very important…The head end crew would pick up the locomotive consist off the outbound ready track and proceed to the train couple up and proceed to pump the air-unless it was already pumped up by a yard airhose…Carmen connected the air hoses and check everything else.We would also check and get a copy of the daily bulletin.We would note any slow orders.
Back then we would also note the caboose number so we would be sure to board the correct caboose since there may be 5 outbounds.That was a safeguard more then anything.
To get 9000 tons to move, and then to accelerate it, you need both HP and tractive effort. A locomotive weighing 230 tons can generate over 100,000 lbs of tractive effort and get a heavy train moving all by itself in the right conditions. The weight of the locomotive and the adhesion of its steel tires on the smooth steel rails have to be such that the tires retain their purchase on the rails and don’t slip. It may be a slow acceleration, but it will happen…all 9000 tons.
Some years ago I read a book entitled “Elements Of Railroad Engineering”. From what I remember, with solid bearings on dry, level tangent track, it would take 6 lbs of pull/ton to get moving. Once moving, the resistance would drop down to 3 lbs/ton and would gradually rise as speed increased. Unfortuantely, I’ve forgotten what the reistance curve looked like as speed increased.
Every tractive effort curve I’ve ever seen for a road steam locomotive indicates that full starting tractive effort could be maintained up to about 10-12 MPH and would decrease from that point, so theoretically, a USRA Light 2-8-2 could start and pull a 9000 ton train on level tangent track. Starting would probably require taking a certain amount of slack, but once moving things would be OK. My guess (and that’s all it is) is that a USRA Light Mike could get the train up to and maintain about 20-25 MPH on dry level tangent track.
As I recall, a UP Big Boy was rated for 4000 or so tons up the 1.14% grades of the Wahsatch. A Big Boy was equal to about 2.5 USRA light Mikes on a tractive effort basis. On the Wasatch grade, the USRA should have been good for about 1500-1600 tons, which seems reasonable given the 500 ton rating for an SP C-8/9/10 (83% of the tractive effort of a USRA Light Mike) in Tehachapi with its ruling grade of 2.52% compensated for curvature. If the SP had had USRA Light Mikes, they would have been rated at about 600 tons in Tehachapi and would have been mor
Andre,I seen single GE and EMD units pulling 100 car trains so,please don’t underestimate today’s locomotives.
Hi, Gas:
When your mind is back to operating status, soon I hope, here is some data on the subject from the American Locomotive Co’s. 1917 Locomotive Handbook…
Lots of useful stuff here, and a great cure for insomnia!
I hope you can read this OK. I scanned it at 300dpi.
Probably more than you’ll ever want to know about train resistance. I remember hearing about the tough sell that Timken and other roller bearing manufacturers had in trying to convince the railroads that they would SAVE money by reducing friction.
Hope this helps you out, Take care-Ed
So have I, but as I said, on dry level tangent track, it doesn’t take much power to move a train. I’d like to see a single SD70ACe duplicate 3985’s effort on Archer Hill. I’m sure it could handle the tonnage, but I doubt it would be moving as fast.
Back in the 60’s, I saw a single F7 moving a long train down the San Joaquin Valley. It wasn’t moving fast, but it was moving. OTOH, SP’s M-6 Moguls were referred to as “Valley Malleys” because they were quite capable of moving substantial tonnage down the valley, and they had only about 1/6 the starting tractive effort that an SD70ACe does and roughly half that of an F7.
Andre
LOL, that was a stupid question. But now that I asked I got to read some very usefull information.
Thanks everyone, and have a great holiday.
MIKE