And probably a dumb one at that. Does the engineer throttle up from notch 1 to a higher notch (like all the way to 8 for example) all at once then control the acceleration by adjusting juice to the traction motors? Or do they …I don’t know …um …“shift” through the notches??( 4000 h.p. and “8 on the floor”).[%-)]
No, simpler than that. The notches directly control the speed and horsepower the diesel engine puts out. The prime mover is directly connected to the main generator, and through advanced electrical controls powers the traction motors. So the more “notches” the engineer uses, the more power is made, and the faster the motors spin.
This is a very generalized overview, but should help you understand it.
Adrianspeeder
Ford? Ford doesn’t even make a real diesel, or a real truck, anymore, do they?
Unless you are talking the old sweep throttles…
First motors I ever ran were 65 tonners, a Porter and GE center cabs. They had sweep throttles, just pull and it increased, let it go, went back to idle. wierd little creatures indeed, 1944 vintage…
Murphy,
Each notch coresponds to a set rpm on the diesel engine, and each preset rpm creates a paticular amount of voltage to the traction motors from the alternator.
Depending on the weight, length and type of train, most engineers will notch it out one or two, take up the slack, then get a few more notches till the desired speed is reached.
Good engineers can make quite a long run without ever doing a brake reduction, just by using the weight of the train and throttle position to slow the train when needed.
Ed
Ya, with what Ed said, i see it all the time. You notch up 1 , 2 or 3 if she’s is really heavy, they move 15 feet to get the slack stretched and go back down to idle, then they pump it up from there.
Alec
Ed: you answered my question thanks! I couldn’t visualize whether the engineer went up through the notches incrementally,as speed increased, or went right from notch 1 to notch 8. Thanks again
I suspect that going straight to notch 8 in today’s locomotives would have some interesting effects, especially with a heavy train. (Ed B recently provided an account of what happens when you “floor” a light engine - more pickup that you might imagine.) Once the horsepower applied to the wheels was enough to overcome the friction between the wheels and the rails, they should start to slip (a long standing problem in the first place), but then the wheel-slip stuff would kick in, although I’m not sure exactly what that would do - override the throttle and back it down?
It’s really no different than driving your car. Too much gas and you spin your wheels, although there is no wheel-slip circuitry to compensate in that case. Keep your acceleration within the limits and away you go.
Thanks Ed for clearing up my post. When I got to run an SD45, the engineer just told me to rip it to 6, I went to 7. hehehehe
Who do you think you are? Go away n00b if you will make stupid comments like that.
Adrianspeeder
Tree…Just a comment on wheel slippage in a car…There is a slippage control now available in autos…Quite a few of them in fact.
Long before Lemp control and its counterparts with the other builders, there were two separate controls for engine speed and generator output. The engineer would notch out the throttle for the engine to a given speed and then adjust the generator output to roughly match the engine speed to control the actual speed of the car. Needless to say, this took a fair amount of skill to operate correctly without abusing the equipment.
So with the wheel slip equipment and the high horsepower,I should be able to do a really nice wheelie?[:o)]
Yeah, I’ve got a wheel slippage control in my 4-cyl Toyota Camry – just floor it and the thing pulls away with this even, gentle acceleration.
What a car. No power to speak of, weak brakes, so-so steering feel, but it gets 36 MPG highway and according to the Insurance Institute for Highway Safety, it has one of the lowest driver-death rates of any sedan that size. Maybe really cautious people drive Camrys.
I had a car like that once. It was a Dodge Aspen. It was a very religious car too. You stepped on the gas, and prayed that you could pull out into traffic without getting killed.
I’m not a fan, if I want the rear to hang out a little, or I want to get a little wiggly, thats my choice.
Adrianspeeder
When they were just converted to diesel, the old engineers used to “notcherup” to fast cause the steam loco took so much power.
What planet are you people from?
The throtttle lever has about 60 notches, and to operate it you pull it back. However, first put the reverser all the way forward, but draw it back as you get up to speed. This can control the cutoff.
Oh…sorry [:)][:D].
-Daniel Parks
trainjunky 29: Sorry man. That went right over my head?
Steam Locomotives:
Throttle controls openinig into steam pipe for amount of steam at any instant into cylinders.
Cutoff controls what proportion of the piston stroke the steam is admitted to cylenders.
Under most conditions you can control the power and thus the speed of the train by either control, although for a given speed and load there is one combination that is most economical.
Me neither - I’ve driven one car with traction control (as it’s called over here) and it was awful. I’d rather just have a nicely balanced pedal that’s not a hair trigger and use my foot and ears to prevent wheelspin. Dread to think what half these electronics will be like in a few years time, especially when the diagnostics gear is no longer available…