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Re: Dynamic braking question
Author: ex-BN
Date: 04-29-2016 - 13:14
Dr Zarkoff Wrote:
-------------------------------------------------------
> >Retainers.
>
> Which Amtrak has never installed on its cars.
>
> >Essentially you set more air than you need (as
> opposed to less air and supplement with dynamic)
> and drag them down the hill.
>
> Retainers hold a certain amount of pressure in the
> brake cylinders while you release the brakes to
> recharge the auxiliary reservoirs.
>
> >Of course it can be done without dynamics but it
> is hard on brake shoes and wheels,
>
> Which have always been designed with this in mind.
> The rule used to be "stop to cool the wheels every
> 10 miles".
>
> >wastes fuel and time.
>
> Oh my, oh my, oh my, the dreaded MBA-driven money
> fixation. How can you waste time if you've
> balanced the grade at or near track speed? How do
> you waste fuel with the engines at idle?
>
> >In 1995 it was common to have non-functioning
> maintaining features on BN locomotives.
>
> Which is pretty late in the CFR/FRA regulations
> game to get away with.
>
> >I've taken 132 ton per operative brake trains
> down 2.2% grade with a non-dynamic unit and a #6
> brake valve. So, yes, it can be done.
>
> BTDT many times myself.
>
> >In steam days it was even harder since riding the
> driver brakes could expand the tires causing them
> to come loose from the wheels.
>
> For this reason, with any locomotive which has
> tires on the wheels, including GG1s, you never did
> this.
I think we all know how retainers work (depending whether set to HP, LP or SD) but thanks for the refresher course.
You waste time walking your train to set and then release retainers. You waste fuel using power to pull a train down hill. Where I'm from you didn't release the air when dragging a train unless you wanted a quick trip the bottom. If you did need to release the air you stopped and tied hand brakes (by rule) to recharge rather than use retainers. Retainers were however used to get steam powered train down the hill since the brake valves would not maintain pressure.
Maybe the SP maintained power better than the BN but it was always common to have non-working dynamic and non-maintaining locomotives. I just used 1995 since it was date referred to earlier. Much of mainline experience was before that. Most of us used the regulating valve since the brake valves were so unreliable.
-------------------------------------------------------
> >Retainers.
>
> Which Amtrak has never installed on its cars.
>
> >Essentially you set more air than you need (as
> opposed to less air and supplement with dynamic)
> and drag them down the hill.
>
> Retainers hold a certain amount of pressure in the
> brake cylinders while you release the brakes to
> recharge the auxiliary reservoirs.
>
> >Of course it can be done without dynamics but it
> is hard on brake shoes and wheels,
>
> Which have always been designed with this in mind.
> The rule used to be "stop to cool the wheels every
> 10 miles".
>
> >wastes fuel and time.
>
> Oh my, oh my, oh my, the dreaded MBA-driven money
> fixation. How can you waste time if you've
> balanced the grade at or near track speed? How do
> you waste fuel with the engines at idle?
>
> >In 1995 it was common to have non-functioning
> maintaining features on BN locomotives.
>
> Which is pretty late in the CFR/FRA regulations
> game to get away with.
>
> >I've taken 132 ton per operative brake trains
> down 2.2% grade with a non-dynamic unit and a #6
> brake valve. So, yes, it can be done.
>
> BTDT many times myself.
>
> >In steam days it was even harder since riding the
> driver brakes could expand the tires causing them
> to come loose from the wheels.
>
> For this reason, with any locomotive which has
> tires on the wheels, including GG1s, you never did
> this.
I think we all know how retainers work (depending whether set to HP, LP or SD) but thanks for the refresher course.
You waste time walking your train to set and then release retainers. You waste fuel using power to pull a train down hill. Where I'm from you didn't release the air when dragging a train unless you wanted a quick trip the bottom. If you did need to release the air you stopped and tied hand brakes (by rule) to recharge rather than use retainers. Retainers were however used to get steam powered train down the hill since the brake valves would not maintain pressure.
Maybe the SP maintained power better than the BN but it was always common to have non-working dynamic and non-maintaining locomotives. I just used 1995 since it was date referred to earlier. Much of mainline experience was before that. Most of us used the regulating valve since the brake valves were so unreliable.
