I would like to know how many maximum cars can a diesel loco pull? Eg. C44-9W pulling coal hopper.
Is there a relationship between horsepower and the weight of all the cars?
Thks, Jimmy
On level track, you mean? Pulling loaded coal cars?
Once the train is rolling, an engine with 110,000 lb tractive effort should be able to maintain 11-12 mph with at least 200 cars-- maybe 300 or more. But if they got stopped, could the engine get the train rolling again? That’s a harder question.
Each locomotive manufacturer provides a chart showing the weight an engine can pull for various grades. Every railroad has a ruling (maximum) grade that determines how much tonnage a locomotive can handle on that stretch of railroad. Some railroads will load a train beyond that and double the hill taking half the cars each time. Other railroads may assign a helper to that area. Still other railroads may use that figure and not put more cars on the train. Railroads also need to be aware of the degrees of curvature involved as that reduces the tonnage further. Yardmasters have been known to overload trains just to clear their yard and relieve the congestion since a stall on the line is not their problem. It really doesn;t matter much if the cars are hoppers or container cars it still comes down to how much tonnage is involved although the higher cars do have more wind resistance and it needs to be accounted for also in higher wind areas.
Yard masters may try and clear the yard but its the crew that says i cant pull it and reduces tonnage, something most all of you have forgot is that its not so much what they can pull its also saftey issues such as braking and in cold weather its very hard to get the air up and maintain proper brake pipe pressures. there is a chart regaurding how many cars a train can haul in the winter time .
I’m with timz on this, its just as much about whether it can get the train started as moving it. As for the original question…one locomotive can actually move a lot. A single GP38 can pull a 10000 plus ton train, assuming the track is level and you weren’t looking to set any speed records. But could it start it is another matter. With slack taken into account it should be able to but there are enough other variables to make it interesting. I read once that a diesel locomotive has to be able to start any train it can technically pull, but a Steam locomotive had to be able to move any train it could actually get started. Or was it vice-versa? I don’t remember where I read it but it was interesting, additional locomotives on a train is often to be able to maintain a greater speed so much as keep it moving. But underpowering isn’t a good idea either. I think this could be an interesting discussion, hopefully more people will add to the topic here.
Or not.
Does weather take a factor in pulling a load? What about the type of Cars?
I remember going across 30 in the mid 90’s and seeing one SD-60M pulling a coal train towards Linclon NE of course it took forever for them to get the SOB up to speed but they could move it.
Weather does I’m sure, and lets not forget wet leaves. I don’t know about cars, I have heard that intermodal cars are inefficient but don’t know if it means they can pull less of them.
In terms of tare weight (the weight of the freight as a percentage of the total weight of the loaded car) intermodal well (stack) cars are one of the most efficient types of equipment and are lighter than many of other types of freight cars (coal gons/hoppers for instance).
Only in railroad fiction – at the three Class Is I know and love.
The yardmaster has no authority to overload the train. The dispatcher will refuse it – he has the trainlist and there’s no way he’s going to give a signal to a train to leave the yard with a hp/ton ratio that exceeds the division’s limits. The yardmaster wants to fudge the trainlist? The train crew will refuse it. It’s a federal violation. The yardmaster doesn’t even have the authority to try to overload the train, that’s up to the terminal trainmaster. The terminal trainmaster can plead his case to the trick dispatcher, who will turn him down, and he can appeal to the chief dispatcher, who will turn him down. Tough cookies.
The yard has to publish to the chief its needs for the next 48 hours. The chief assigns trains to lift the tonnage and the power desk assigns power to pull the trains. If the yard goofs and has more tonnage than locomotives, then they can try and explain themselves to the superintendent and the regional GM on the next 0700 conference call to everyone else’s amusement.
If a train falls down because of too much tonnage, that’s the chief dispatcher’s problem. He’s not ever going to take an overtonnage train unless he is ordered to do so, in writing or with witnesses, by the Regional VP or GM. If it falls down because of bad power, that’s mechanical’s problem – but if it’s due to a known bad-actor locomotive or class of locomotive, the chief will get reamed for allowing the power desk to let a train out with such crap on the pointy end.
I regularly turned down grain trains that one of our major terminals tried to foist on me with junk SD45s from one of our connections. On paper they would barely pull the first ruling gra
I didn;t say it was common I just said it has been known to happen and not in modern times. Weather does play a factor as cold temperatures will cause higher resistance primarily to the grease in the wheel bearings and take longer to pump up air.
You are correct, however, this still occurs, primarily on inter-divisional run through trains, where the train is built the ‘flatlands’ a division or two or more away from where the ground has a more vertical nature. The Flatland Yardmasters have been known to load the trains to the tonnage rating for the flatland areas and thereby dump their overloads on the unsuspecting terminal that adjoins the more vertical division when that division refuses the train. A similar situation occurs when trains are built in flatland area the must traverse areas with Helper Districts and the Yardmaster puts HAZMAT in the rear 5 cars…now in addition to adding helper power to the rear of the train, cars must be found to bury the HAZMAT.
A junk SD45 ?!?!?!? Not possible !
Sure it is. Most any non-WC (or MRL) SD45 would probably fit that description.
Sometimes engines can pull more than they should, for short distances. I had this engine by itself one night.
Went out to pull a train in. I thought there were 20-some cars, probably 1500-2000 tons. Nobody told us about the 25 grain loads (3250 tons) they picked up on the way. The place we started out from was downhill a bit, so it started just fine. When we came to the hill leading to the yard, we found out there was a little more tonnage than we thought. Got down to about 4 mph, Run 8, sparks shooting out of the stack, and feathering the independent to keep from slipping. Made it into the yard, though.
Todays railroads are more than willing to put 4997 tons behind power rated for 5000 tons. I think there is about 1 hp per ton right?
Dependent on the engines and the territory. One territory that I am aware of has a GP-38 with 2000 HP rated for 7500 tons per unit. Other territories, of a more vertical nature, have a CW44AC rated for 2250 tons
Following is the rating in tons per unit for a CW44AC over various adjoining territories.
5750
9950
5050
10500
6300
9000
8200
9100
9100
9450
9000
5750
2250
As can be seen - there is a wide variation in what one unit can handle, depending upon the territory.
It depends on the type of train.