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  • What Kind of Air Brakes Am I Talking About?

  • General discussion about locomotives, rolling stock, and equipment
General discussion about locomotives, rolling stock, and equipment

Moderator: John_Perkowski

 #134224  by UPRR engineer
 
I cant remember what they were called if anyone knows, this is what i posted on General Discussion: Railroad-Specific: Short Lines and Industrials where steam was asking about shortline guys.


Wish i knew the correct name for those old style air brakes, someone looking might know though. L26 or R23 something like that. Newer style automatic air brake go threw these settings starting at released, initial, service zone, full service, supression, handle off, and emergency. Running with the old style that was on the SW units i ran went starting from release, lap, service zone..... i dont even think they had supression, maybe they did though, handle off, then emergency. So on newer style brakes when you move from the release position to initial or all the way to full service nothing else is required to hold and maintain the air you have set (unless the pressure maintain feature is bad, then you move it into the PASS position). On the older style you would come out of intial past the lap position into the service zone till you've drawn off the amount you want, then shove the hand back, into lap, or it would continue to suck the air out of the cars, crappy crappy set up. Even in lap it would blead off and set more air. We use to come off some scare hills with Hazmat cars at the plant. Keeping her at 10MPH was nearly impossible, you had two choices, tip toe off the top, let her rock and roll till you got close to the bottom and then use the air, or scream off the top with a couple pounds set hold her in the 8th run and you might make the bottom without having to kicker off. I had my share of rides in the cab and riding the last car. I had to do the moves up on the caustic hill that first time i got to play hoghead all by myself. So steam if you heard a hog complain about the air on those older SW locomotives you know what there talking about now.
Last edited by UPRR engineer on Mon Jun 06, 2005 9:36 pm, edited 1 time in total.

 #134232  by MikeF
 
The old brake valves to which you refer were type 24RL. No, they didn't have suppression. The positions, counter-clockwise, were release, running, lap, service and emergency. The handle could be removed in the lap position. The deadman feature was automatically suppressed when the brakes were fully applied (about 30 psi cylinder pressure).

The newer self-lapping valves are type 26L (or 26C on a lot of commuter cab cars and MU equipment).

 #134238  by UPRR engineer
 
Unlike most new hogs now a days (after the caboose) having put up with the 24RL might be the cause for me liking the air more than the dynamic brakes when i run. I can remember the day the SW's went out and the UP brought us some Geeps, we were all AMAZED that you could set the air and it would hold it and not bleed down. Funny thing about that, it was sometime in 1995 when that happened. We were like a couple old steam hogs looking at the first diesel locomotive to come threw.

 #134480  by Aji-tater
 
On those 24RL brakes you forgot to mention "first service" which was between running and lap.

Some 24 brakes were equipped with a pressure maintaining feature which compensated for train line leakage.

 #134484  by LCJ
 
Aji-tater wrote:Some 24 brakes were equipped with a pressure maintaining feature which compensated for train line leakage.
Yeah -- a crappy one the often didn't perform as designed.

The 24 system was good for passenger operation with graduated release, where BP leakage was negligable. I enjoyed running E8s with it in late PC, early Amtrak era (and on CR office car trains).

 #134560  by MikeF
 
Aji-tater wrote:On those 24RL brakes you forgot to mention "first service" which was between running and lap.
Oh yeah. I thought I was forgetting something.

I can't remember and I don't have a manual handy -- what did "first service" do?

 #134562  by LCJ
 
MikeF wrote: -- what did "first service" do?
A 6 to 8 lb reduction. The same function as the minimum reduction position on the 26, except 26's gave you a 5 to 7.

 #135269  by BlackDog
 
Never saw 24RL on a switcher, all I ever saw was a version of 6ET, I believe it was 14. The independant shared a bracket type casting with the automatic, whereas 6ET the independant was separate.

I never got to work with 24RL, though I would like to give it a shot.

 #135272  by LCJ
 
LCJ wrote:
MikeF wrote: -- what did "first service" do?
A 6 to 8 lb reduction. The same function as the minimum reduction position on the 26, except 26's gave you a 5 to 7.
The purpose of the first service and minimum reduction positions was to take advantage of the accelerated quick service feature of the AB control valve on freight equipment -- getting just enough brake cylinder pressure up to move the piston out, and putting the shoes up against the wheels to start getting them warmed up and sticky.

Here's how it works in the AB control valve.