Air Brake... 26L / 6 SL combination

I resently came across a SW8 locomotive that was equipped with 26L brake valves in the cab (26C, SA-26) and 6 SL under the floor (6-KR and H5B). Never saw or heard of this before... Is this a mod that was fairly common or a mickey mouse job? Any info would be great! Especially for trouble shooting this system..... Thanks.

I've got a NYAB book from 1978 that details the conversion of 6 brakes over to 26NL brakes using the 6NR dist. valve. I think the 6KR has slide valves, where the NR has spool valves.

email me and I'll scan the schematic in the book and send it to you.

TxBritt

I recently did that conversion on an SW9 and it works well. One thing I have not resolved is the size of the Equalizing Reservoir - the 26 uses a smaller one, IIRC it's about 220 CI while the one on the old system appears to be closer to 1000. It makes for slightly longer response time when making a reduction but other than that no problem.

The portions retain their respective maintenance intervals - the 26 parts go 3 years while the below-the-floor stuff gets changed out after two.

Are the 6 SL valves still easily available? They must be getting rare.
Do you have any info on brake testing units this set up? I'm only familiar
with testing 26L systems. One of the stange things I found on the 2 units with the mixed system, you can't bail off in emergency.
Thanks.

Without looking at the papers I'm running the risk of error but I believe bail-off was done with a relay valve. Also I remember I had trouble with the independent not applying with a reduction of the automatic - turns out you need an...H5B??...instead of a plain H5.

There are several variations on the basic design, depending on whether your unit has MU, dead man pedal, etc.

One source of the valves is Multi-Service Supply, 412-741-1500. We don't do the testing and rebuild, just UTEX the various valves.

My paperwork says its an H-5-B, with a 25lb spring.

Britt Bettell

The 2 units I worked on have the H5B... It bails off ok on the automatic application... but not the emergency... Maybe thats the way the 6SL was...
I dunno...
Never had the pleasure of playing with one...

That does not sound right - it should bail off regardless of what initiated the application, service or emergency. I will have to see if I can find the piping diagrams. What do you have on it - A1 charging cut-off? MU2A or no?

The units I worked on were not set up for MU.
So there was no MU2A or A1.
It's a simple system.. Only the 26C, SA26, 6 NR or 6 KR, H 5 B,the KM-2 vent valve and some check valves...When the bail off was depressed in emergency.. it would vent.. and brake cyl PSI would drop.. but not to 0.

26 NL was the NYAB designation for the what has been described.

JFD

Yes, Txbritt noted that in the second post. It's a good system from what I can see.

MLW - That sounds like the same set-up we have, non-MU. Saturday is busy but somewhere over the weekend I'll try to locate the piping diagram. Actually another member of this forum sent it to me a couple years ago and I finally got around to doing it in May 05. I have an A-1 mounted but have not hooked it all up yet - if the air goes in emergency we quick cut the brake valve out to save MR pressure. The A-1 will take care of that.

BR&P
The addition of the A1 sounds like a good idea....
I have a schematic that Txbritt kindy sent me...
I would be interested in your schematic as well...

Is the 26 NL fairly common in the US???
Seems the very rare in Canada.

txbritt wrote:I've got a NYAB book from 1978 that details the conversion of 6 brakes over to 26NL brakes using the 6NR dist. valve. I think the 6KR has slide valves, where the NR has spool valves.

email me and I'll scan the schematic in the book and send it to you.

TxBritt

Could you share or email this information to me fo this air conversion? Thanks. [email protected].