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Re: Ed, that is my experience,with the physics of choo-choo's as well.
Author: Hot Water
Date: 01-23-2018 - 14:43
BOB2 Wrote:
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> You are trying to create friction to slow down, by
> the process of conversion of the energy from the
> mass and momentum of the moving train into heat
> energy. The momentum energy is being dissipated
> in the heat from the brake shoes interacting with
> the wheels, the more surface area the more heat
> dissipated, the quicker you stop.
>
> Sliding the wheels dramatically reduces the amount
> of the surface area creating friction, and the
> heat that can be dissipated, to just the much
> smaller surface area of the wheel in contact with
> the rail head. It is, thus, much less effective in
> transferring the energy from the mass of the
> moving train into heat energy, and stopping the
> train or cut you are handling. There were times
> when I even used a slight bit of power, along with
> sand, to make sure I didn't slide the wheels, and
> lose much of that greater friction and the heat
> energy being created.
>
> Reversing the engine, if it results in sliding the
> wheels. is not going to stop you faster, in my 18
> years of experience. But, I've had my butt
> tightened, up not a few times, in situations like
> that, where I wish I could have thrown an anchor
> out, though.
>
> You are protected by law from reporting unsafe RR
> conditions. And, while I've seen folks threaten
> over that, I've never seen anyone successfully
> removed from service for that.
>
> As I noted about this thread, we have so little
> real factual information about what really
> happened or why he was really purportedly pulled
> out of service, that all of this is speculation.
> And while it's been a while since I've run, I was
> certainly not impressed by the little bit of the
> story we were told, with the train handling skills
> he is reported to have used in this situation, him
> being RR "family", or not.
Very well detailed explanation, and very accurate. Only one other item to consider; with DC traction units, in many cases the "throwing the reverser into reverse" while under power, many times trips the ground really, and thus NOTHING HAPPENS.
-------------------------------------------------------
> You are trying to create friction to slow down, by
> the process of conversion of the energy from the
> mass and momentum of the moving train into heat
> energy. The momentum energy is being dissipated
> in the heat from the brake shoes interacting with
> the wheels, the more surface area the more heat
> dissipated, the quicker you stop.
>
> Sliding the wheels dramatically reduces the amount
> of the surface area creating friction, and the
> heat that can be dissipated, to just the much
> smaller surface area of the wheel in contact with
> the rail head. It is, thus, much less effective in
> transferring the energy from the mass of the
> moving train into heat energy, and stopping the
> train or cut you are handling. There were times
> when I even used a slight bit of power, along with
> sand, to make sure I didn't slide the wheels, and
> lose much of that greater friction and the heat
> energy being created.
>
> Reversing the engine, if it results in sliding the
> wheels. is not going to stop you faster, in my 18
> years of experience. But, I've had my butt
> tightened, up not a few times, in situations like
> that, where I wish I could have thrown an anchor
> out, though.
>
> You are protected by law from reporting unsafe RR
> conditions. And, while I've seen folks threaten
> over that, I've never seen anyone successfully
> removed from service for that.
>
> As I noted about this thread, we have so little
> real factual information about what really
> happened or why he was really purportedly pulled
> out of service, that all of this is speculation.
> And while it's been a while since I've run, I was
> certainly not impressed by the little bit of the
> story we were told, with the train handling skills
> he is reported to have used in this situation, him
> being RR "family", or not.
Very well detailed explanation, and very accurate. Only one other item to consider; with DC traction units, in many cases the "throwing the reverser into reverse" while under power, many times trips the ground really, and thus NOTHING HAPPENS.
