Steam & Excursion > Question on brake schedules

Not sure where to ask this, but I figured this would be the best place. I have a question. What are the main diferences between the brake schedules found on locomotives. I often hear them refered to at 26L (that seems to be the prefered on). 6BL, 24RL and such. I read an article somewhere that mentioned the SPS steamers had 8EL. What do all these mean? Can someone list all the diferent types and what thier diferences are?

Thanks

indyspy Wrote:
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> > Not sure where to ask this, but I figured this
> would be the best place. I have a question. What
> are the main diferences between the brake
> schedules found on locomotives. I often hear them
> refered to at 26L (that seems to be the prefered
> on). 6BL, 24RL and such. I read an article
> somewhere that mentioned the SPS steamers had 8EL.
> What do all these mean? Can someone list all the
> diferent types and what thier diferences are?

The A-1 brake was introduced in 1895, using a straight air brake on the locomotive and Automatic brake for handling the train. The locomotive brake was completely independent of the automatic brake, and even though it is now interdependent with the automatic brake, the name "independent" has stuck.

In 1905 the 5-ET brake was introduced. This brake added a number of components which caused the locomotive brakes to apply and release at the same time as the train brakes, or the locomotive brakes could be applied and/or released separately, or the locomotive brakes could remain applied when releasing the automatic brakes.

In 1906 the 6-ET was introduced, which had the same functionality as the 5-ET, but the parts and plumbing were greatly simlified and combined into fewer units.

The engineer on 6-ET uses an H-6 automatic brake valve for the control of the train brakes, and an S-6 brake valve to control the locomotive brakes. This brake and its variations was pretty much the defacto standard until 1957.

S-6 brake valve positions:
1) Quick release - Quickly releases the independent brake. Spring loaded, the valve cannot be left in this position without holding it manually. This position will also release the independent brake after having been applied with the automatic brake valve.
2) Release - Normal release and running position, but will not release the locomotive brakes if the have been applied with the automatic brake valve (exception: See H-6 "holding" position definition, below).
3) Lap - After a brake application the brake valve is moved to the lap position to hold the appication without increasing or decreasing locomotive brake cylinder pressure.
4) Service - Normal application position. When the desired application is achieved, the handle is then moved to lap to hold it.
5) Quick service - applies independent brake more quickly. Also spring loaded, and cannot be left in this position.

H-6 brake valve positions:
1) Release - allows full main reservoir air pressure to pass to the brake pipe. In later years, most railroads disabled this position.
2) Running - allows air pressure at the setting of the feed valve to pass to the brake pipe, and releases the locomotive brakes if applied by an automatic brake valve application with the S-6 brake valve in the release position.
3) Holding - Same as running, except does not release the independent brake. This position is internally programmable, and may be cut out.
4) Lap - After applying the brakes with the automatic brake valve, the handle is moved to the lap position to neither add nor remove air from the brakepipe. However, a No 6 brake does not compensate for leakage, except in the "running" position.
5) Service - Reduces the pressure in the locomotives equalizing reservoir at a rate of 2 1/2 psi per second. The engineer does not control the reduction of brake pipe pressure in the train directly, but he controls the equalizing reservoir. The lower portion of the H-6 valve then reduces the brake pipe pressure at a controlled rate (so as to avoid going into emergency) until the brake pipe pressure is equal to the equalizing reservoir. The purpose of this is so that, regardless of the length of the train, the engineer has control of the same volume of air (that of the equalizing reservoir), and does not have to allow more time for the larger volume of air from a longer brake pipe to be exhaused - the brake valve takes care of that compensation for him. A service application of the automatic brake valve also applies the locomotive brakes at a service rate.
6) Emergency - Opens a large exhaust hole from the brake pipe to the atmosphere, to cause an Emergency application of the train and locomotive brake.

6-DS, 6-BL, and 6-BLC brakes are modifications of the 6-ET brake, with modified piping controls to regulate diesel powered compressors, rather than steam, and have modified brake stands, though their operation is the same, except when an LA6-P independent brake valve is used instead of the S-6. The LA6-P is self lapping, that is it has an application zone between release and full application: The farther the handle is moved to the right the greater the application - the handle is moved to the left to reduce the application, or depressed to release the locomotive brakes when applied by the automatic.

14-EL brakes are modified 6-ET brakes with control lines for electrically powered motor driven air pumps on electric locomotives, and with a K-14 engineers brake valve. The K-14 combines the S-6 and H-6 valves into a single unit, and has a slight internal piping modification which allows for quicker release of the independent brake when using the quick release position.

14-EL and 6-BLC brakes may be set up for MU capability.

I'm out of time, right now - I'll write more tonite about the 8, 10, 24, 26, and 30's.

My first post addressed the early Westinghouse systems. New York had similar competitive systems, but with some variations, especially in the earlier years. Over time, New York tended to follow what Westinghouse was doing, and by the late '40's parts were so compatible that you could even order gaskets from New York and use them in Westinghouse valves!

New Yorks LT-1 was the approximate equivalent of Westinghouses No 6, except early versions retained the straight air brake for the independent. New York's B1-B was approximately equivalent to Westinghouse A-1.

The original concept of the A-1 was that passenger engines did not require independent brakes, and were not equipped with them. The locomotive did not have independent brakes, but instead the engine and tender each used a plain Type F triple valve and was regarded by the brake system as just one more baggage car.

9 1/2", 11", or cross compound air compressors, or dual compressors of any size, could be swapped out on any of these systems, and New York duplex compressors could be substituted on Westinghouse systems and vice versa.

I've only touched on the primary parts of the plain vanilla systems. There were other alternative parts that could be used, such as S-3 (straight air) independent brake valve, or a G-6 instead of H-6 automatic brake valve and the changes that would be required to the regulating and feed valves to accomodate the changes. I received a private e-mail this afternoon from a user of a modified No 6 distributing valve that cut out the Holding feature of the H-6. Over time, most engines became basterdized or hybridized by the railroads shops, and it's not uncommon to find K-14 valves on steam engines, either.

The 8-ET system introduced some improvements to the 6, by replacing the holding position on the L-8-PA brakestand with a position called first service. This forced the engineer to make a 6 psi brake pipe reduction on his first reduction, which is required on the AB family of brakes used on freight cars. With earlier F, K, L, N, P, and UC valves used on cars, an engineer can functionally make a smaller reduction of the brakes, but while it is not fully reliable, the H-6 engineers valve will accomocate it. It takes real skill, and it's not without risk, but with those early valves and a G-6 to control them you can darn near control each car on a short train separately. But with longer trains, added safety features need to be mandated and the L-8-PA began to do this.

I am told, however, that with a long train on a long descending grade with H-6 brake valves on the engine, it was possible for the engineer to virtually divide his train into three segments, and transfer braking power from one segment to another without the use of retainers, to allow one segment to cool off while another did the work of slowing the train! I can visualize how this could be done - but, one would have to have brass balls to try it!

The 10 systems further advanced this concept. I have not run 8 or 10 systems myself, and have little information on the 8's and virtually nothing on the 10's, so I hope someone with some feel for these things will jump in here on this subject.

The No 24-RL brake combines the best elements of the 6, 8 and 10 systems. It has an independent brake similar to the LA6-P. It is programmable, and various features can be cut in and out - some by switching a lever, and others in the shop by changing components. It has Release, Running, First Service (quickly takes minimum 6psi reduction, then continues to slowly reduce brake pipe until moved to lap), Lap, Service, and Emergency positions. Programmable functions include Retarded recharge, Dead engine, Graduated release, Safety control, overspeed control, Cut out first service, controlled release, split reduction, and brake pipe maintaining. The independent brake on a 24 system is similar to the LA6-P. I know of 3 major variations of the brakestand for this system, which differ in the way first service is taken, in how maintaining is handled, and the appearance of the independent brake. But, for all of its features, the 24-RL was kind of a kludge. I prefer to cut out maintaining and first service on these brakes, and just think of it as a tall H-6.

In 1957 the 26L brake was introduced, and quickly became standard. The 30CDW and electronic brakes of today are fucntionally identical to this brake, as well. The 26-SA independent brake valve has the same positions as the LA6-P. The 26-C automatic brake valve also has an operationg range, with the following positions: Release, Minimum reduction (similar to the 24's first reduction, it forces a 6 psi brake pipe reduction when brakes are first applied), Service Zone (the farther the handle is moved to the right, the greater the reduction), Supression (for recovery after a system induced safety "penalty" brake application), Continuous Service (shich can reduce to 0 if desired), and Emergency.

Another piece of information would be of interest. Having had a brief experience with locomotive operation (running an NW2 on a private track), it was necessary to periodically spill a little brake air because of a pressure buildup. I don't know if this is common to all brake systems and the people who allowed me this opportunity could not explain it in any detail. It seemed odd but I have noticed it in various train videos when cab operation is shown, even on 4449!

So what is the reason for this? Has it ever been addressed? Is there a way that the need for this action could be eliminated? You get the drift. It would be interesting to know.