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Peco Hydraulic Buffer Stop - is there a prototype?


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On 05/03/2018 at 11:19, Oldddudders said:
On 05/03/2018 at 10:12, luckymucklebackit said:

Not dissimilar to the buffers at Glasgow Central, although they have been modified with a support frame

 

19000152078_7776e06e46_c.jpgSafety First by Steve Hallam, on Flickr

 

Jim

I knew a girl with hydraulic buffers - and they certainly needed a support frame.

Found the level, then...

 

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Happy to be corrected but I'm fairly sure they had them at Swansea High Street, a terminus at the bottom of a steep bank.  I remember commenting in a letter to the guard's inspector when the Swansea MAS scheme came on line that I considered it bad practice to have a green signal to enter the platforms from the gantry next to the entrance to Malefant Sidings.  To my mind, the next signal should have been regarded as the red light on the buffers, a stop signal, and thus this gantry should have not been able to display a green light, only a yellow.  He replied that driver's route knowledge should prevent any mishaps in this distinctive location, and I thought of Salisbury, Shrewsbury, and Grantham, Norton Fitzwarren, Harrow and Wealdstone, and Eltham Well Hall, and the effect of a contact at even a low speed with the hydraulic buffers on a train full of passengers reaching up to the overhead racks for their bags, or fumbling between the seats, or already hanging out of open doors (this was the 70s) that would either slam shut on them or chuck them out at some velocity.  But management had spoken, and it was not my place to to question further; I had a copy of the correspondence and would have brought it out if the sh*t had hit the fan...

 

My grim imaginings were brought to reality at Canon Street, but I couldn't tell you what aspect that train entered the station under.  I had left the railway by that time.

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Those support frames at Glasgow are to support the centre pads where modern EMU centre couplings will make contact, without thos a collision would make a right mess of the car end.

Whenever there is space friction controlled sliding buffers (Rawie) are prferred now as they can absorb the momentum energy in a more controlled manner over a longer distance and hence minimise damage and injury.

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On 05/03/2018 at 10:09, russ p said:

Were they pressurised with oil or water or were there both sorts?


In London, I am pretty sure with water supplied under “high” pressure By the London Hydraulic company.

 

I think that the action is that, as the buffer is compressed, water is forced out of the cylinder through a valve sized to give a particular retarding force - it’s a shock-absorber. I don’t think it’s the “mains pressure” directly that provides the retarding action. [Wrong! The water either moves round a piston, or through sized apertures in a piston  ........ this is the US version of the background patent That Ransomes had rights to exploit https://patents.google.com/patent/US271478 ]

 

 

Edited by Nearholmer
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The buffers are not pressurised as such just filled, pressure to force the water out is provided by the train pushing the ram in. So there is no heed for high pressure water from a hydraulic main. That was for lifts and cranes etc.

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9 hours ago, Free At Last said:

What is the purpose of the tank you sometimes see mounted next to them?

According to the tank at Lancaster it is air:

 

1488766969_Buffers1.jpg.a5e897a049200f5f0573ec8701bb57a2.jpg

 

119772351_buffers2.jpg.8369a4e570e3f0e7d53910a56becfb43.jpg

 

2008525411_buffers3.jpg.8399a76932210134aa42d2a3f6926241.jpg

 

buffers.jpg.5cfe4d31503fcc1964ed07d2704192d9.jpg

 

Doesn't look like anythings touched them in years.

 

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I’m going to try to find out more, because I suspect that these beast do have to be pressurised, possibly to extend them after they’ve been compressed.

 

Air seems like a very odd choice though, because, like steam, it is very easy to get it wrong and create explosive forces.

 

Is that air reservoir definitely part of the buffer set-up, not something else?

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24 minutes ago, Nearholmer said:

 

Is that air reservoir definitely part of the buffer set-up, not something else?

Follow the blue pipework. It all ties up. Out of the front bottom of the buffer cylinder casing, all 4 teed together and into the front of the air tank. The tank is pre-pressurised.

 

Can't see how it works unless the air is to keep the buffers pre-loaded.

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From a pressure vessel perspective, that reservoir needs an inspection every 14 months (Yearly). The volume of the cylinder will need to accept the volume of compressed material (Gas- oil or other) delivered by the buffer piston.  If it's air, then it'll discharge to atmosphere. If its a liquid, it'll need a recognised discharge pipe, pipe pathway, and drain. If you have a boiler at home, then you will have a similar arrangement. In general terms, it's called D2 work, and it falls within building regulations. The cylinder might well be pressurised, as I espied a pressure gauge on the photo. I also notice a plant tag on the cylinder, so it's on a pressure vessel register somewhere. 

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1 hour ago, tomparryharry said:

From a pressure vessel perspective, that reservoir needs an inspection every 14 months (Yearly). The volume of the cylinder will need to accept the volume of compressed material (Gas- oil or other) delivered by the buffer piston.  If it's air, then it'll discharge to atmosphere. If its a liquid, it'll need a recognised discharge pipe, pipe pathway, and drain. If you have a boiler at home, then you will have a similar arrangement. In general terms, it's called D2 work, and it falls within building regulations. The cylinder might well be pressurised, as I espied a pressure gauge on the photo. I also notice a plant tag on the cylinder, so it's on a pressure vessel register somewhere. 

 

 

Buffer testing at Glasgow Central used to be a regular occurrence, ,don't know if they still do it but the last time it was noted on the scot-rail enthusiasts site was in October 2017 when 37424 was noted buffer testing on platforms 6 and 7 

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2 hours ago, rockershovel said:

I’m sure they were installed at Moorgate.

 

I'm also pretty sure they were installed at Paddington, and Waterloo also?  I'm sure the informed ones amongst you will know.

 

I'm also fairly sure that platform 8 or 9 at Waterloo still has its water overflow catch pits. These would allow the fireman to put on its injector without flooding out the surrounding track area. 

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Three of the Terminal Stations in Buenos Aires have them as well.

 

Constitucion..

9-467.JPG.80278bfde0b410d51c80afd2f83c8179.JPG

 

9-368.jpg.9894f43e5a36835f59f9b7822beac3c3.jpg

 

One of the Retiro termini..

 

7-1700.JPG.df6ded4028996ab6ef3ed19c963feffc.JPG

 

and whilst they are all fully working at these two stations, they were not, but deactivated/still in situ at Once terminal...

 

7-1638.JPG.eb8f5da93f0e15d0dbdf111b55c94396.JPG

 

which didn't help when this happened 5 years after I photographed them...

https://en.wikipedia.org/wiki/2012_Buenos_Aires_rail_disaster

 

The inquiry team investigating the crash did find my photos proving they weren't in use to be quite helpful........

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7 hours ago, melmerby said:

According to the tank at Lancaster it is air:

 

1488766969_Buffers1.jpg.a5e897a049200f5f0573ec8701bb57a2.jpg

 

119772351_buffers2.jpg.8369a4e570e3f0e7d53910a56becfb43.jpg

 

2008525411_buffers3.jpg.8399a76932210134aa42d2a3f6926241.jpg

 

buffers.jpg.5cfe4d31503fcc1964ed07d2704192d9.jpg

 

Doesn't look like anythings touched them in years.

 

 

The sign in the background says hydraulic buffers, so, the tall tank could well be a charging cylinder with a nitrogen charged diaphragm in the top half, similar to a sealed system in a domestic central heating boiler, to maintain the charge pressure.

 

Mike.

 

Mike

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1 hour ago, Enterprisingwestern said:

 

The sign in the background says hydraulic buffers, so, the tall tank could well be a charging cylinder with a nitrogen charged diaphragm in the top half, similar to a sealed system in a domestic central heating boiler, to maintain the charge pressure.

 

Mike.

 

Mike

The vessel was definitely pressurized (unless the gauge was stuck!)

I just assumed it would be air, there also appears to be a (safety?) valve on top.

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8 minutes ago, tomparryharry said:

Without inspecting it, it should most likely be air. The upright vessel says the makers panel is a compressor body, and if it's water, it'll be lagged. Any pressurised cylinder will have a safety valve.

The maker's label says it's BS EN286 pt1 and Class 1, unfortunately the pressure is obscured by the tag!

 

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1 hour ago, 25901 said:

Bradford's set

WP_20161113_15_52_34_Pro.jpg

I asume they are now out of use and retracted?

They ain't going to absorb much energy like that, there also seem to be some friction buffers in front of them.

 

Yes, found a picture when they were still in use:

A_Bumper_Spectacle_-_Platforms_2_and_3_-

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