Air and vacuum braked vehicles

[jim.snowdon]

3 hours ago, David Charwelton said:

I am now thinking of the marshalling of freight trains. Would the shunters decide the order of the vehicles? From the point of view of having a fitted head of sufficient length, presumably the shunter would not marshal any vehicles having the 'wrong' braking system in the head even if through piped? How was it ensured that the right pipes were connected if vehicles were fitted and through piped? Did air and vacuum pipes have different connections?

 

Regards, David

Air brake and vacuum brake pipes have very different connections, as well as sizes, so connecting the two is an impossibility (unless you really set out to defeat the system by making a adaptor).

 

 The make up of goods trains is determined, essentially, by where the wagons are going. Ignoring block trains, the trains that connected the main marshalling yards would be made up in blocks for the various yards at which they called. That may mean that if the front section is dropped off at an intermediary yard, with its fitted head, there may be a second 'fitted head' further back in the train for the next stage of the journey. The requirement was to have sufficient fitted vehicles at the head for the class of train, not every fitted vehicle in the train.

Local goods trains, that dropped sections off at individual stations, would be organised in station order, but not necessarily sequentially. Because of varying station layouts, some station might be served on the outward trip and others on the return. All designed for ease of operation. 

 

Jim

[Wickham Green too]

5 hours ago, David Charwelton said:

......  How was it ensured that the right pipes were connected if vehicles were fitted and through piped?  ......

The connections for - shall we say - 'operative' or through pipes would have been physically identical so they were totally compatible .... but the hose coupling itself and/or the adjacent fixed pipe ( where visible ) was normally painted differently : the actual colours changed over the years just to confuse matters. ( Then you get even more colour confusion with two-pipe brakes and pull-push air connections but they're outwith the scope of this thread.)

[Nick Holliday]

On 30 April 2020 at 08:04, David Charwelton said:

So were any goods vehicles that were not intended to run in passenger trains fitted with dual brakes?

 

Regards, David 

In general, most goods vehicles that were continuously braked were those that might be incorporated in passenger trains as they carried cargos that were perishable or urgent. These would include meat vans, sometimes refrigerated, fruit vans, fish trucks and cattle wagons, and perhaps specialist items such as eggs, flowers or silk. But that didn't preclude them for running in goods trains if the timings were suitable, loaded or empty.

However, on at least the Lancashire and Yorkshire Railway, around 1904 they introduced a number of high capacity open wagons, and they were concerned about braking forces on their often steep and busy lines, and after tests concluded that continuous vacuum brakes would provide more force than regular hand brakes, and many subsequent wagons were fitted with vacuum brakes. 

I think that post-grouping a larger proportion of the wagon stock was fitted with vacuum brakes, so it became more common to find such fitted stock in general goods trains.

6 hours ago, jim.snowdon said:

Air brake and vacuum brake pipes have very different connections, as well as sizes, so connecting the two is an impossibility (unless you really set out to defeat the system by making a adaptor).

I think I have read that Westinghouse pipes were 1 inch in diameter and vacuum 2 inches. The connectors would be of different designs too,  as they had to work in different ways in order to make an effective seal.

6 hours ago, jim.snowdon said:

 The make up of goods trains is determined, essentially, by where the wagons are going. Ignoring block trains, the trains that connected the main marshalling yards would be made up in blocks for the various yards at which they called. That may mean that if the front section is dropped off at an intermediary yard, with its fitted head, there may be a second 'fitted head' further back in the train for the next stage of the journey. The requirement was to have sufficient fitted vehicles at the head for the class of train, not every fitted vehicle in the train.

Given the relatively low proportion of fitted vehicles I think it would sometimes be quite a task to have sufficient of them to create the required fitted head in that way. If I have interpreted Bob Essery's notes correctly, the way a fitted freight would be assembled was to have all, or most, of the fitted stock at the head. They would be sorted with, usually, the wagons for the final destination at the front, with the other fitted stock sorted in reverse order of dropping off, let's say A-B-C-D. The non-fitted stock would then be marshalled the other way, D-C-B-A, resulting in a sequence A-B-C-D-C-B-A. At the first dropping off point the train would be split, and the wagons for D shunted out of the train, and any wagons picked up added, although I am not sure how they would be sorted to make things easier at the next stops. Ignoring them, the train now consisted of the sequence A-B-C-B-A, and the wagons for C would be split out of the train at the next stop. This process should ensure that the correct proportion of fitted stock is maintained throughout the journey.

6 hours ago, jim.snowdon said:

Local goods trains, that dropped sections off at individual stations, would be organised in station order, but not necessarily sequentially. Because of varying station layouts, some station might be served on the outward trip and others on the return. All designed for ease of operation. 

 

Jim

This works with local trips, and for branchlines ending with termini, where the return working would be fairly soon after the outward trip. But many lines had quite long services, stopping at all stations along the route, and in these instances either the wagons for the errant stations would be dropped off at the next suitable yard to be picked up by the next train working in the opposite direction, or their wagons would have been routed in a slightly different way so that they were travelling in the correct direction to be easily shunted; sometimes quite easy to arrange considering the complexity of the railway networks in some areas.