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Re: Dynamic braking question
Author: Dr Zarkoff
Date: 04-29-2016 - 10:44
>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.
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.
