GWR ATC ramp positions

[WillCav]

Hi all,

 

I've been reading up on GWR ATC ramps as I've found one on a photo and I'm not 100% why it was there.

 

One book says 200yds behind the distant, whereas the other two say 1/4 mile back. I assume the 200yds was confused with AWS positions.

 

the scenario I have found is the ramp is  beyond pointwork beyond an inner (slotted) distant - but the line is bidirectionally signalled with a turn back move starting the other side of the ATC ramp.

 

David J Smith's book says that a slotted outer distant has its ramp 20yds beyond the signal.

 

Were slotted inner distants ever fitted with ATC ramps?  Would a fixed outer distant on approach make a difference to the ATC arrangement?

 

The actual ramp was between signal 'A' and 32(a) pts at Cheltenham Malvern Road East.

 

Thanks

 

Will

[The Stationmaster]

Every one is right!

 

The ramps at independent semaphore distants were officially quoted as the following distance in rear of the signal -

1920 'about 400 yards'

1936 'usually 440yds in rear of the signal'

1960 '440 yards in rear of the signal'

But I wouldn't be surprised if that distance was sometimes reduced on slower speed lines.  

The distance for multiple aspect colour light signals was 200 yards in rear of the signal.

 

Ramps applying to lower arm distant signals were fixed slightly in advance of the signal although the distance might have varied a little due to various factors but you can usually reckon about an engine length (a tender engine).  If you buy Warners new 'Smoke and Steam' bookazine you will find an excellent illustration of ramps in advance of  lower arm distants but you can no doubt also fnd such things on the 'net.

 

In the case of all distants, including lower arm distants, it made made no difference it the signal was an outer, Intermediate, or inner distant - they were all provided with a ramp, even if they were fixed at caution.  But - with one experimental exception - ATC ramps were not used on single lines.

[TheSignalEngineer]

22 minutes ago, The Stationmaster said:

But - with one experimental exception - ATC ramps were not used on single lines.

The profile of the ramp was not designed for being hit at speed in the wrong direction. The slope at the running on end is 1 in 90 and the trailing end is 1 in 32.  

Always a right bu**er if it arrived up the wrong way round on the wagon and needed to be turned, especially in a cutting. 

[The Stationmaster]

7 minutes ago, TheSignalEngineer said:

The profile of the ramp was not designed for being hit at speed in the wrong direction. The slope at the running on end is 1 in 90 and the trailing end is 1 in 32.  

Always a right bu**er if it arrived up the wrong way round on the wagon and needed to be turned, especially in a cutting. 

Interestingly the original profile was very different and  looked to be almost level over the length of the ramp but presumably that was quickly found to be impractical so the final inverted fishbelly (sort of) profile was adopted.

[5BarVT]

1 hour ago, The Stationmaster said:

In the case of all distants, including lower arm distants, it made made no difference it the signal was an outer, Intermediate, or inner distant - they were all provided with a ramp, even if they were fixed at caution.

I thought I had read somewhere that only the first distant was fitted.  I wonder if the rules changed over time? Or perhaps I am just plain wrong!!

Paul.

[Michael Hodgson]

1 hour ago, TheSignalEngineer said:

The profile of the ramp was not designed for being hit at speed in the wrong direction. The slope at the running on end is 1 in 90 and the trailing end is 1 in 32.  

Always a right bu**er if it arrived up the wrong way round on the wagon and needed to be turned, especially in a cutting. 

A problem in Single Line Working ? 

If it's Box A to B you probably shouldn't pass a ramp bang road, but you would encounter Box B's ramp if the working is Box A to Box C. 

[WillCav]

Thanks everyone for your input on this.

 

I'll make sure I have the steep end pointing in the normal direction of travel.

 

The wrong direction signalled move would be starting from rest, so low speed over ramp.  With Single Line Working, speed is low as well.

 

Thanks again

 

Will

 

 

[Miss Prism]

4 hours ago, TheSignalEngineer said:

The profile of the ramp was not designed for being hit at speed in the wrong direction. The slope at the running on end is 1 in 90 and the trailing end is 1 in 32. 

 

Thanks. (I had always assumed the ramps were symmetrical !) Presumably though, those used on the Fairford branch (single line) were symmetrical?

 

[Miss Prism]

Some sheds had shortie 'ATC testers', often in pairs it would seem. Here's one at Reading, c 1930:

 

[WillCav]

There's good info on the dimensions of both the mainline and shed exit ramps in the recent book by David J Smith if anyone needs to make any.

 

Will

[TheSignalEngineer]

2 hours ago, Miss Prism said:

 

Thanks. (I had always assumed the ramps were symmetrical !) Presumably though, those used on the Fairford branch (single line) were symmetrical?

 

I think the prototype ramps were symmetrical. To get the same profile for each direction would require the inverted T-bar on the ramp top which was 44'3" long to be extended by approximately 12'.

They took quite some hammer at speed and I remember seeing them with a dip worn into the top in the area where the shoe made contact with the bar.

 

 

2 hours ago, Miss Prism said:

Some sheds had shortie 'ATC testers', often in pairs it would seem. Here's one at Reading, c 1930:

 

 

Shed test ramps did come in pairs set at the limits at which the height of those in the main line could be set. The nominal height of a full ramp was 3.5" above rail level. 

Another use of ATC ramps was to latch up the shoe when running onto 3rd/4th rail electrified lines. These were set at 4.5" above rail level the running in ramp being a dead one which pushed the shoe up onto the latch. The running out ramp was live and this unlatched the shoe so it dropped back to the operational position.

 

1 hour ago, WillCav said:

There's good info on the dimensions of both the mainline and shed exit ramps in the recent book by David J Smith if anyone needs to make any.

 

Will

There is a paper to the GWR Engineering Society giving a description of the system here http://www.gwr.org.uk/notes/P_206.pdf

It includes dimensions of the ramp about six pages in.

[5BarVT]

8 hours ago, TheSignalEngineer said:

Another use of ATC ramps was to latch up the shoe when running onto 3rd/4th rail electrified lines. These were set at 4.5" above rail level the running in ramp being a dead one which pushed the shoe up onto the latch. The running out ramp was live and this unlatched the shoe so it dropped back to the operational position.

Many thanks Eric.  I knew about the running in ramps, but didn’t know that running out was also automatic.

Paul.

[Miss Prism]

9 hours ago, TheSignalEngineer said:

There is a paper to the GWR Engineering Society giving a description of the system here http://www.gwr.org.uk/notes/P_206.pdf

 

I'd forgotten I had included that. (doh!)

 

[The Stationmaster]

The shoes on engines used to suffer considerable wear too - finishing up with a noticeable grove in the actual contact piece before it reached the limit for renewal.