Does anyone have; info, photos, drawings, anything on the very early brake line hose couplers that had a built-in check valve to stop the air flow in case of a separation?

These were introduced on the early straight air brake systems offered by WABCO?

The Nevada County NG must have been one of the last users of these.

These early valves preceded the brake line angle cock (still used today) mounted on each of the car ends that contains the brake pressure within the cars brakes when the brake line is separated.

I can't imagine anything like that being used on a regular automatic air brake installation where you want air to be released in the event of an accidental separation.

Steve

"straight air" is the difference here.

Straight air brakes had no automatic or fail safe features. When you pressurized the train line, the train brakes came on. When you reduced the pressure on the train line you also reduced the braking power. no pressure, no braking.

This first straight air brake system was still much better than the sytem before it; straight air on the locomotive and hand brakes on the train. Each brakeman had to apply each brake by running on the tops of the train cars to apply and also to release each hand brake. It was; slow, weak, dangerous and time consuming (expensive). This is the way it was for a long time.

The problems were also many with the straight air system. It was slow to pressurize the train line, this caused long delays in braking. That caused the front of the train to apply the brakes before the rear of the train, this caused great damage to the front of the train as the rear cars crashed into the slowing front cars. This system would only allow short trains because of its problems.

The problems were solved, to a large degree, with the triple valve; "the 18th centuries greatest invention". We still use a form of triple valve on 98% of freight and passnger trains today.

read this; http://www.wabtec.com/corp/history.asp

So in the case of a break in two, this type of check valve used with straight air would leave the brakes operational on the leading portion, and if air had been applied prior to the break, it would leave that air set on the trailing section.

I have seen a reference to this check valve feature in a patent search on early automatic railroad air couplers. It seems like I have seen a reference to it somewhere else more recently, but I can't recall where, and that seems improbable because it conflicts with the fully automatic brake.

I had been told about these by a friend who is a most serious student of air brakes. I am not sure if he had ever seen one; if not, he would diffidently want to.

I wonder why those interested in a fail-safe brake system without the complications of the automatic air brake (mines etc.) didn't create a system where brakes are applied by a heavy spring whose force is counteracted by an air cylinder. Let the air out and on come the brakes. Sort of like the emergency portion of semi-truck brakes. It might even be made compatible with automatic air brakes (just need to make an adjustment control where you set the car to whatever trainline pressure is going to be used OR you standardize to some pressure).

Steve

I managed to pick up a copy of the 1888 Car Builder's Dictionary off of eBay recently.

Low and behold on page E125 such a brake hose coupler is shown as figure 327. It is a spring operated check valve that depresses when coupled to another hose, allowing the air to pass. When the hoses uncouple, the spring-operated valve rises, closing the gap.

Google Books has the 1879 edition and a similar drawing:

http://books.google.com/books?id=RqoMAQAAIAAJ&pg=PA468#v=onepage&q&f=false

Here it is cut out;

http://books.google.com/books?id=Jv7VAA ... 413&edge=0

Thanks, that is what I was looking for!