P42 speed control and acceleration

[lrh442]

How do Amtrak trains running diesel electrics (e.g. P42 Genesis) maintain a more-or-less constant 79mph (or whatever the track speed is)? Is there some form of electronic cruise control? It seems that the engineer constantly moving throttle notches to hold a steady speed would not be nearly precise enough to hold the steady speeds that I see on my GPS or on the track recordings.

On a related question, when accelerating from a stop on dry rail to track speed does the engineer gradually and sequentially increase run positions or can they skip notches?

 

[Acela150]

I believe that the P42's and P40's are equipped with Cruise Control. I know that the ACS-64's, AEM-7's, HHP's, and Acela sets have a cruise function. I have seen them used first hand.

As to "Notching out" as it's referred to. Each engineer is different. But it's best to take Notch 1 then go to 2 and then open it up. That's only for passenger service though. If you had a freight unit or freight train it's best to notch out one notch at a time.

 

[Qapla]

I found these comments with a Google search:

Cruise control works on a passenger unit, such as an Amtrak Genesis P42, because passenger equipment is equipped with near-zero-slack couplers (type H "tightlocks" with machined coupler faces) and obviously train lengths and weights are much lower than most freights.

Amtrak's P42DC are the only units equipped with cruise control. Well when they work. They seem to frequently malfunction

Amtrak's P40's and P42's and both MNCR and Amtrak P32acdm all have cruise control.

 

[railiner]

How do Amtrak trains running diesel electrics (e.g. P42 Genesis) maintain a more-or-less constant 79mph (or whatever the track speed is)? Is there some form of electronic cruise control? It seems that the engineer constantly moving throttle notches to hold a steady speed would not be nearly precise enough to hold the steady speeds that I see on my GPS or on the track recordings.

Bear in mind, that a moving train is very heavy, and the laws of inertia should more or less mean the train should maintain its speed for a while, before additional power is needed to modulate that speed...much more so than say in your car on a highway...not to mention railroads don't have the steeper grades of a highway...

 

[Thirdrail7]

On a related question, when accelerating from a stop on dry rail to track speed does the engineer gradually and sequentially increase run positions or can they skip notches?

Instructions governing the Genesis fleet and the Charger Fleet (particularly when they are in push-pull service) specify using one notch at a time, with a pronounced interval between them.