the power and the struggle of 2 engines

[brakemen]

hello to all:

in my city there were an sd60 ns hauling 15 grain cars stoped at the switch yard droped off the 15 grain cars and picked up 28 grain cars and left now it had no problems hauling the 15 grain cars to this switchyard here in the city. now comes a gp 38 ns parked at the yard picked up the 15 grain cars as it struggle for speed. the engineer moves the throttle up at the half way point and the engine struggled but with only 15 full grain cars really?? and once again the engineer moved the throttle full throttle the gp 38 strained for only 15 full grain cars and again really?? witnessing the the weak gp 38 in action or in this case not in action for only 15 full grain cars struggleing this engine will never make it as a 20 or 25 long train car haul. if it cannot handle the 15 cars without struggleing the gp38 will never make as a long train haulling. why use a weak gp38 ns when near by there is a ns sd60. oh by the way the ns sd60 hooked up with the 28 grain cars and the engineer put it into full throttle and in a few mins it was gone. nice strong engine to be able to handle those many cars and then can carry more than that. then came the weak gp38 in the switchyard unable to handle more or less 15 grain cars. why keep an engine at the yard if it cannot handle anything larger than 15 cars. I on another day I also witnessed at the switchyard, the same weak gp38 tried to handle a 20 full grain cars the weak gp38 just stood there full throttle and going nowhere. now that is just plain weak gp38 really. the engineer had to move the throttle back down to stop and try again and same thing happened did not move all. and I guess the engineer called someone because in a couple of hours an sd70 came to the yard and took over the 20 grain cars unhitched the weak gp38 rehooked the sd70 with the grain cars and moved full throttle and he was gone.

I wish I had some pics for you seening a weak gp38 in action maybe not in action trying to move those 15 cars and later the 20 cars ( but did not have my camera with me.

brakemen

 

[Azervich]

Grain is also very heavy, your looking at around 70-90ton per car, and don't forget that older locomotives only sustain series-parallel for slow speed heavy pulling (probably 0-12mph) then locomotive will change into parallel which is for high speeds and not heavy pulling.

 

[KingConrail76]

And you are somehow surprised, or angered, or confused that a 2,000 HP 4 axle GP38 can not handle the same load as a 6 axle 3,800 HP SD60 or 4,000 HP SD70 ??

 

[Azervich]

I on another day I also witnessed at the switchyard, the same weak gp38 tried to handle a 20 full grain cars the weak gp38 just stood there full throttle and going nowhere.

They might have also been charging brake pipe, the longer the train is the more time it takes to charge the brake pipe, before moving any train you need at least 60PSI in the brake pipe so you have enough air in the aux res to stop with minimal brake, the air compressor is also linked to the engine, when the engine is idle (258rpm) air compressor also runs at that speed, so to get air pumped up fast you throw it into a high notch to get it to run faster, roughly 1,700 liters/min at 900rpm if it's a WXE Type

But on level track a 2,000hp locomotive will move 3000 imperial tons easy in a series-parallel field.

 

[kws4000]

20 full grain cars, if new, weigh about 287K pounds per car, = 2800 tons. GP38 generates 61000 pounds TE starting. That works out to perhaps 21 pounds per ton here, which ought to be enough. I highly doubt that the yard was on a grade, and .7 hp/ton is quite enough for slow speed switching. I would suspect there are other conditions we are not aware of, or the geep might need significant repairs if it won't load up properly. Otherwise, I believe you are correct in figuring that the GP38 should be able to pull said load. And FYI: Please improve your use of punctuation, its your friend in helping people understand you; sort of like a caboose or observation car.

 

[mhicaso]

The GP38 is a good locomotive, I work with them a lot and have actually been impressed with what they can handle. There is a good chance it is a case of what Azervich explained, or there could have been a ground fault in one of the traction motors. If that is the case, it does not matter what throttle position they were in, as soon as it hit a certain voltage the engine would have dropped it's load and to you it would have sounded like the engineer was moved his throttle back to idle even though he had not.