Parralel brake systems.

[railfan365]

I've been wondering about something that I haven't seen much information on. That is: Why do locomotives have separate brake handles for locomotive braking, to be used while deadheading, and train braking, to be used with cars hitched up? Isn't air braking the same, no matter how long the train is? (Allowing of course that reaction time will get longer as cars are added without adding locomotives).

[DutchRailnut]

The independent brake (locomotive(s) is used primarily for switching , not road use.
In Automatic brake ( train brake) the locomotive(s) brake can be bailed off for smoother train operation.

[RDGTRANSMUSEUM]

if they had only the "big brake" as it is called,the locomotive wheels would slide if you could not bail them off (with the independent)when braking a train. Also the ind brake works faster,great for switching with out air in the cars. You need both brakes in railroading.

[DutchRailnut]

Hmm wheels would not slide, lots of railroads these days absolutely prohibit bailing off on locomotive brakes.

[Jtgshu]

Hmm wheels would not slide, lots of railroads these days absolutely prohibit bailing off on locomotive brakes.

ive had locos which when the blended (dynamic) brake came on, the brake cylinder didn't release a corresponding amount and gave almost instant wheel slide from the dynamic braking force being added to the already high brake cylider pressures. I had to bail off to prevent making square wheels. Of course, that SHOULDN'T happen, but it did.

[RDGTRANSMUSEUM]

yep,i was always taught to bail them off to prevent sliding and never had a problem.

[DutchRailnut]

Hmm wheels would not slide, lots of railroads these days absolutely prohibit bailing off on locomotive brakes.

ive had locos which when the blended (dynamic) brake came on, the brake cylinder didn't release a corresponding amount and gave almost instant wheel slide from the dynamic braking force being added to the already high brake cylider pressures. I had to bail off to prevent making square wheels. Of course, that SHOULDN'T happen, but it did.

Last time I looked the FRA requires Electronics to prevent sliding, they are a lot faster than you or me.

[Jtgshu]

Hmm wheels would not slide, lots of railroads these days absolutely prohibit bailing off on locomotive brakes.

ive had locos which when the blended (dynamic) brake came on, the brake cylinder didn't release a corresponding amount and gave almost instant wheel slide from the dynamic braking force being added to the already high brake cylider pressures. I had to bail off to prevent making square wheels. Of course, that SHOULDN'T happen, but it did.

Last time I looked the FRA requires Electronics to prevent sliding, they are a lot faster than you or me.

When im trying to make suppression in a Geep going 100mph due to a cab signal change and the loco brake cylinder doesn't bleed off fast enough when the dynamic/blended brakes come on and the wheels lock up, and my speedo drops to 0 and i hear that sound of sliding metal wheels going very fast, im gonan keep that in mind..... the electronics are turning on the buzzer on the control stand and going ERRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR at me - not helping the situation a whole heck of a lot.....speedo is still 0mph while we are still moving at close to triple digit speeds.

wheels get real square real fast going 100mph to 0mph in .5 seconds. Also, with the way the blended braking is set up on NJT geeps at least, even if you bail off, and release loco brake cylinder (and in turn the dynamics) if you take out more air, usually about 30psi, the dynamics/blended come back on with less brake cylinder. It DOES stop you significantly faster than just letting it ride with the wheels locked up.

anyway, i guess my rr is one of the apparent "lucky few" that still allow bailing off. Go us!

[DutchRailnut]

I guess the MMC is not as good as some claim