[steamer_ctn]

It is proposed to add functionality for the Eames vacuum brake system.

The Eames Braking system was used in older train and tram braking systems. Some more info can be ascertained here and here.

It has two major differences to the existing braking systems:

i) It was a straight (plain, non-automatic) brake system, ie it had no auxiliary reservoirs, and the vacuum operation in the train brake pipe was the reverse of modern systems, ie Vacuum on = brakes on, vacuum released = brakes off. Hence a straight brake system couldn't apply the brakes if the train brake pipe was broken, and it was considered a safety issue, and they didn't seem to last long for main stream train operation.

ii) Operation of the brake required the driver to use two different brake valves - one for releasing the brakes (exhaust the vacuum), and one to apply the brakes (create a vacuum).

[darwins]

The "Eames brake" was the version of the simple vacuum brake produced in USA. The brake was used by some railroads in the US and also installed in some vehicles exported by USA. It was not widely adopted as "Automatic" brakes such as the Automatic Vacuum Brake and the Automatic Air Brake that could stop both parts of a train if it become divided were starting to appear at about the same date.

Another country that used the simple vacuum brake was Austria. This document includes a description of the braking systems used by Austrian Railways.

Technische_Mitteilungen4.pdf

The Appendix gives details of the braking equipment fitted to various classes of locomotive and rolling stock. From this it can be seen that many locomotives were built with the Simple Vacuum Brake up until the early years of the 20th century. These included classes that became Imperial Royal Austrian State Railways classes 15, 59, 66, 73, 97, 102, 166 and 560.

Two classes of tank locomotive class 169 and class 199 were able to operate both Simple Vacuum Brakes and Automatic Vacuum Brakes.
KkStB_169
KkStB_199

Section L pp18-19 describes how these locomotives be used to operate either the Automatic Vacuum Brake or the Simple Vacuum Brake.

They had two different brake handles for the different systems and changeover switches for the brake valves and ejectors.

The brake controllers for the Simple Vacuum Brake had 3 positions

>Los< - RELEASE - allowed air to enter the brake pipe and brake cylinders

>Mittelstellung< - LAP or NEUTRAL - used as a running position or to hold a brake application

>Fest< - APPLY - supplied steam to the large ejector, creating a vacuum, which applied the brakes

[darwins]

There were also several classes of locomotive fitted with a "Reversible Quick Acting Vacuum Brake" (Umschalt-Vakuum-Schnellbremse). These locomotives used the same brake controller for both systems, with the function being changed by reversing switches on the brake handle and ejector.

For Automatic Vacuum Brake operation:

RUNNING - can be used to create a vacuum with the large ejector or to maintain the vacuum in the train pipe using the small ejector

moving slowly towards
TRAIN BRAKED - gradually opens the valve that lets air into the train pipe and applies the train brakes only, but not the locomotive brakes, this was used for service braking.

ALL BRAKED - applies both locomotive and train brakes by letting air into both the train pipe and the engine brake cylinders - used for emergency braking.


For Simple Vacuum Brake operation:

RELEASE - opens the valve that lets air into the train pipe and also into the locomotive brake cylinder, releasing the brakes.

LAP or NEUTRAL - used as a running position - also as a lap position to maintain vacuum in brake pipe

moving slowly towards
TRAIN BRAKED - gradually opens the valve that lets steam into the large ejector and applies the train brakes only, but not the locomotive brakes, this was used for service braking.

ALL BRAKED - steam is supplied to the large ejector, vacuum created in both the train brake pipe and the locomotive brake cylinders, both locomotive and train brakes applied - used for emergency braking.


Noted that there are two names for the Simple Vacuum brake that are not used for the Automatic Vacuum brake. As there are no pictures of the brake handle then it is difficult to tell how these positions relate to each other.


Imperial Royal Austrian State Railways classes 24, 30, 60, 106, 205, 308 and 406 were fitted with "reversible vacuum brakes".

[steamer_ctn]

Work has continued on implementation of straight (non-automatic) vacuum brake functionality, and work on the Hardy brake system is now complete.

A demonstration model can be downloaded from CTN.

Thanks to Darwin Smith and Roger van Duijnhoven for their testing expertise and knowledge.

It would be good if a few people could take it for a test run to confirm all is ok.

The Eames brake system will follow shortly.

[steamer_ctn]

Work has continued on implementation of straight (non-automatic) vacuum brake functionality, and work on the Eames brake system is now complete.

A demonstration model can be downloaded from CTN.

Thanks again to Darwin Smith and Roger van Duijnhoven for their testing expertise and knowledge.

It would be good if a few people could take it for a test run to confirm all is ok.