I was wondering if some could explain basically how the air brakes work on steam locomotives. My understanding is that there are 2 brakes; the train brake and the engine (independent) brake. The train brake is maintained at 70 psi for freight and 90 psi for passenger and the independent brake maintained at 110 psi. The independent brake only applies the brakes on the engine but the train brake applies brakes on both the engine and the train. Most engines have 2 reservoirs; 1 for the train air, and the other for the engine and air operated locomotive accessories such as the bell, whistle, power reverse, etc. hence the 100 psi.

Is this basically how things work? Also, larger engines tend to have 3 or four reservoirs. What are they used for?

Thanks for your help.

> The train brake is
> maintained at 70 psi for freight and 90 psi
> for passenger and the independent brake
> maintained at 110 psi.

No; independent brake cylinder pressure is usually 35 or 40 pounds on steam. Anything more than that invites flat wheels the first time the brakes are used.

Train line brake pipe pressure varies according to the rules of each railroad, but generally, freight is usually in the 70-90 pound range, and passenger is 105-110 pounds.

>Most engines have 2
> reservoirs; 1 for the train air, and the
> other for the engine and air operated
> locomotive accessories such as the bell,
> whistle, power reverse, etc. hence the 100
> psi.

Most have 3, but how many doesn't matter; what does matter is the total volume of all reservoirs. The reservoirs serve all functions; they are not broken out as you described. Mainreservoir pressure is usually maintained at 120-130 psi or 130-140 psi, again depending on the rules of the particular railroad.

A good discription of how air brakes work and some of the more modern variations are on Train Web at:

http://www.trainweb.org/railwaytechnica ... brakes.htm

Ed

Air Brakes on TrainWeb
ff1044@aol.com

Also check out this site:
http://www.sdrm.org/faqs/brakes/history/

air brakes
mtillger@adelphia.net

Besides the equalizing piston and equalizing tank each locomotive system has a distributing valve. On many steam locomotives and early diesels this was a #6 Distributing Valve. This resulting in the air system being called 6ET on locomotives (engine & tender). A essentially identical valve was the #14 used on electric locomotives with the 14EL (Electric Locomotive) schedule.

The distributing valve performs the work of making the locomotive brakes work from either the train air line or from the independent brake valve.

Brian Norden

> The distributing valve performs the work of
> making the locomotive brakes work from
> either the train air line or from the
> independent brake valve.

Interesting question (probably Dave G. would
know): are there any preserved engines that
still have a separate plain triple valve and
double-check valve?

webmaster@bera.org

Being active with the Rockhill Trolley Museum (RTY), there is one statement at the end of that page that I will back up. That is that it's harder for new operators to learn to stop than to learn to go. With a trolley, anybody can turn the controller on. It's much harder to learn how to make a decent stop. The same effects would hold true on a railroad.

Matthew Mummert

http://www.trainweb.org/railwaytechnica ... brakes.htm

> Ed


mlmummert@suscom.net

> Interesting question (probably Dave G. would
> know): are there any preserved engines that
> still have a separate plain triple valve and
> double-check valve?

This is the SWA (Straight With Automatic) system (or "schedule"), and there are lots of them still around.

> Interesting question (probably Dave G. would
> know): are there any preserved engines that
> still have a separate plain triple valve and
> double-check valve?

The engine I help on has the old "High Speed" #5 where the engine/tender and train work off the same brake pipe through plain triple valves. The automatic brake valve has the old leather diaphram feed valve (its at the right height in the cab to hit your knee on). It is in the process of be upgraded to 6ET.

> The engine I help on has the old "High
> Speed" #5 where the engine/tender and
> train work off the same brake pipe through
> plain triple valves. The automatic brake
> valve has the old leather diaphram feed
> valve (its at the right height in the cab to
> hit your knee on). It is in the process of
> be upgraded to 6ET.
Upgraded to 6ET???? That makes no sense. UPGRADE it to 26 NL at least. Sorry I hate 6,14 and 24 brakes!
Give me some form of 26!

irss@eriecoast.com

> Upgraded to 6ET???? That makes no sense.
> UPGRADE it to 26 NL at least. Sorry I hate
> 6,14 and 24 brakes!
> Give me some form of 26!

The 6 brake has to be one of the best brake systems ever built, save the pressure maintain features of a 26L. Some of you may (will probably) disagree, but the manual lap 6 brake for the independent gives the engineer the most repeatable and responsive independent brake applications available. You have to find that "sweet spot" every time you set the brake on a self lapping independent, and you might as well glue your hand to the independent or it will kick off with anything less than 30psi in the cylinders. Give me an Alco S-1 with original equipment to switch with anyday. I'd drop $100 on the table no one would know if the slack is in or out. (I had good teachers up on the WVRR)

Now the 24RL, there is a brake system that has a whole love/hate thing going on. Everybody hates it and it loves to cost money to maintain. The geeps are going to get 26L conversions, but the steamers are going to get 6's!

Ryan

lima709@usadaily.net

> The 6 brake has to be one of the best brake
> systems ever built, save the pressure
> maintain features of a 26L. Some of you may
> (will probably) disagree, but the manual lap
> 6 brake for the independent gives the
> engineer the most repeatable and responsive
> independent brake applications available.
> You have to find that "sweet spot"
> every time you set the brake on a self
> lapping independent, and you might as well
> glue your hand to the independent or it will
> kick off with anything less than 30psi in
> the cylinders. Give me an Alco S-1 with
> original equipment to switch with anyday.
> I'd drop $100 on the table no one would know
> if the slack is in or out. (I had good
> teachers up on the WVRR)

> Now the 24RL, there is a brake system that
> has a whole love/hate thing going on.
> Everybody hates it and it loves to cost
> money to maintain. The geeps are going to
> get 26L conversions, but the steamers are
> going to get 6's!

The 6ET schedule equipment is still in use around the world and it is approaching 100 years since introduction.

The 6ET like old triples, etc. needs proper care and feeding. These have brass slides on brass seats and pistons and rings -- if you don't have the patience I suppose o-rings and diaghrams are for you.

The 5ET was produced for such a limited time to me it makes since to make the change to 6ET.

Brian Norden

Railway Magazine info & subscriptions

> The engine I help on has the old "High
> Speed" #5 where the engine/tender and
> train work off the same brake pipe through
> plain triple valves. The automatic brake
> valve has the old leather diaphram feed
> valve (its at the right height in the cab to
> hit your knee on). It is in the process of
> be upgraded to 6ET.

Are you a museum or a tourist RR?

Please, if you do go ahead and "upgrade" to a
more modern system, don't throw away the old
pieces!


webmaster@bera.org