>In the 1887 Burlington tests WAB and Eames added electricity to their systems and reduced their times from head end to rear end of 50 cars commensurate to that achieved by Carpenter's electri-air brake in 1886

The Burlington Trials were for determining what was necessary for controlling slack in emergency brake applications when trains became longer than about 35-40 cars. The Eames (vacuum), WABCo (pressure), and the buffer brake systems made by American, Rote, etc all failed in the 1886 trials. The MCB's determinations were, based on the relative success of the Carpenter and Hanscom electro-pneumatic systems: air to operate the brakes, electricity to control the air flow. The 1887 Burlington Trials, which included the Eames and WABCo electro- add-ons, essentially reinforced this. Convinced that adding electrical apparatus wasn't necessary, later in 1887 GW made his QA modifications to his plain triple valve, equipped a 50 car freight train with them on his own, and commenced touring around the US. It wasn't an MCB sanctioned series of tests, nor part of the Burlington Trials. The QA feature worked so well, that the MCB approved it in 1888. Afterwards, electro-pneumatic brakes died out except for services like transit and certain passenger trains in which there were limited numbers of specialized cars. This is still true today, including the relatively recent "electronic" brakes for captive service unit freight trains.

Getting back to the OP's questions:

>What speed does train line brake pipe air travel at above 32 degrees?
>What speed does train line brake pipe air travel at below 32 degrees freezing?

In all of my air brake books, air flow speed isn't even mentioned, let alone addressed. While it's true that Westinghouse was always concerned with raising and lowering the pressure at the rear of the train as harmoniously possible with the front -one of his early inventions even used a steam venturi to speed up air flow within the brake pipe- describing the process as the speed of the air flowing through the pipe wasn't done because it's related to the pressure differential between the front and the rear of the train, which is essentially indeterminable at any given instant because it varies so greatly depending on the use and state of the brake system. So I looked on the internet, and for air velocity rates in pipes, see: [www.physicsforums.com] and [en.wikipedia.org] Please by all means work the formulae out for yourselves because I'm no math whiz.