Oval vs Round - Buffered if I Know!

[Wickham Green too]

1 hour ago, davefrk said:

...... the latter two only the front ones, ....

Trouble is, nobody ever photographed the tender behinds - if I may put it like that - so we can't be totally sure what was fitted : Numerous ex S.E.C.R. 4-4-0s received large-headed Maunsell buffers at the front* over the years and I THINK some, at least came from mogul tenders - but rear end photographic evidence of either type is extremely thin on the ground.

 

* also tank engines at the overhang end

[Pandora]

The Britannia class had round buffers, but 70045 Lord Rowallan had oval buffers during the final years,  was 70045 unique or were other members like 70045?

[icn]

On 07/09/2022 at 00:27, melmerby said:

Or the offset trapezoidal version on the Stadler/Vossloh locos (Class 68/88)

Trapezoidal shapes have been around for quite a bit longer than those two - for example the Swiss IC2000 and EW IV stock (although both of those have an additional cut on the outer side). Mk5a's have it too... all to do with push-pull operation I suspect?

 

Having done some further investigation, the oldest trapezoidal version I've found might be this train from 1971 although its unclear whether it had those buffers at time of construction (I suspect they did since I can't find any photos with other buffers): https://de.wikipedia.org/wiki/Doppelstockwagen#/media/Datei:Bf_Rochlitz,_Doppelstockgliederzug.jpg

[melmerby]

3 hours ago, icn said:

Trapezoidal shapes have been around for quite a bit longer than those two - for example the Swiss IC2000 and EW IV stock (although both of those have an additional cut on the outer side). Mk5a's have it too... all to do with push-pull operation I suspect?

 

Having done some further investigation, the oldest trapezoidal version I've found might be this train from 1971 although its unclear whether it had those buffers at time of construction (I suspect they did since I can't find any photos with other buffers): https://de.wikipedia.org/wiki/Doppelstockwagen#/media/Datei:Bf_Rochlitz,_Doppelstockgliederzug.jpg

I know they have been but not AFAIK in the UK

[Steadfast]

On 10/09/2022 at 15:01, icn said:

On 06/09/2022 at 23:27, melmerby said:

Or the offset trapezoidal version on the Stadler/Vossloh locos (Class 68/88)

Trapezoidal shapes have been around for quite a bit longer than those two - for example the Swiss IC2000 and EW IV stock (although both of those have an additional cut on the outer side). Mk5a's have it too... all to do with push-pull operation I suspect?

What I can't suss is the benefit that has over a rectangle the wide of the bottom edge. Weight saving is marginal. Also, you'd thing if anything the shorter edge would be at the bottom, to assist access to the air pipe cocks. At least that'd offer a reason for the shape!

 

Edit time: I've been googling, and according to Wikipedia it's to allow for gangway connections. So why the 68s and Mk5a outer ends need them is beyond me!

 

Jo

Edited September 12, 2022 by Steadfast

[Aire Head]

1 hour ago, Steadfast said:

So why the 68s and Mk5a outer ends need them is beyond me!

 

Commonality of parts thereby reducing the logistical burden perhaps 🤷🏼‍♂️

[Steadfast]

1 hour ago, Aire Head said:

 

Commonality of parts thereby reducing the logistical burden perhaps 🤷🏼‍♂️

Ha, that'd be joined up thinking!

No buffers on the intermediate Mk5As and the 68s and Mk5As have different buffers, just the shape of the head that's the same

 

Jo

Edited September 12, 2022 by Steadfast

[jim.snowdon]

3 hours ago, Steadfast said:

Edit time: I've been googling, and according to Wikipedia it's to allow for gangway connections. So why the 68s and Mk5a outer ends need them is beyond me!

68s are also used by Chiltern with Mark 3 stock, which does have gangways, besides which it makes sense to allow for operation with gangwayed stock - it increases their usefulness (and sellability).

[Steadfast]

1 hour ago, jim.snowdon said:

68s are also used by Chiltern with Mark 3 stock, which does have gangways, besides which it makes sense to allow for operation with gangwayed stock - it increases their usefulness (and sellability).

True enough!

Though the 67s that worked previously on Chiltern don't, and it looks like the vast majority of mixed traffic locos on the continent have full rectangles too. Strange one, presumably specced by Beacon on purchase. 

 

Jo

[844fan]

I know it was exceedingly common (most likely to prevent buffer lock after all very short bases here) that industrial tanks had very big buffers. Take the Port of Parr twins you know.

[The Johnster]

Spot on, 844, small industrial 0-4-0s often had very short wheelbases in order to negotiate very tight curvature; 6’ was typical.  This resulted in proportionally considerable overthrow on said sharp curves, which in turn increased the risk of buffer lock, resulting in the customer specifying large diameter buffers.  

[Wickham Green too]

.... or just large lumps of wood instead.

[LMS2968]

11 minutes ago, Wickham Green too said:

.... or just large lumps of wood instead.

That was the point of 'dumb' or 'dead' buffers. They were effectively just lumps of wood and couldn't buffer lock. But they weren't much good at absorbing the impact when wagons were pushed together either, or compressing on the inside of tight curves.

[Wickham Green too]

Dead / dumb buffers on wagons were normally little more than extensions to the solebars - so not much bigger than a 'conventional' buffer head, and could slip past each other just as easily as the latter on dodgy track ............. clearly they didn't have heads which could then catch behind their neighbours but they could still lock sufficiently to cause a derailment.

[LMS2968]

I was thinking more of locos, such as the various Pugs, the L&YR examples are the ones I know but many similar engines had them, and buffer locking was the reason. The first of the L&YR engines were built with sprung, round buffers but these were soon replaced.

 

But even with wagons, if there was an overlap they could easily be pulled apart again.

[Morello Cherry]

On 06/09/2022 at 19:13, HGR said:

The rectangular buffer appears to be a popular European take on the oval.

 

 

 

And the Isle of Sodor :) 

 

Who knew the Fat Controller was embracing leading edge European design. 

[844fan]

On 13/09/2022 at 09:31, Wickham Green too said:

.... or just large lumps of wood instead.

 

On 13/09/2022 at 09:45, LMS2968 said:

That was the point of 'dumb' or 'dead' buffers. They were effectively just lumps of wood and couldn't buffer lock. But they weren't much good at absorbing the impact when wagons were pushed together either, or compressing on the inside of tight curves.

True enough. Dumb Buffers likely were more for gas works and the like where if I ever saw that tight a bend I wouldn't even think Rocket could manage. And the wheel base on Rocket wasn't more than 15 feet with tender? That kind of tightness would require very, very large buffers if sprung so big I imagine it would keep breaking the mounts. But that is my opinion.

[DCB]

On 07/09/2022 at 18:40, Pandora said:

The Britannia class had round buffers, but 70045 Lord Rowallan had oval buffers during the final years,  was 70045 unique or were other members like 70045?

It needed replacement buffers during overhaul at Crewe after he last LMS Pacifics had been withdrawn and Crewe had a set of refurbished Duchess buffers in stock which had the correct fixing bolt pattern so they used them. Simple as that. 

The oval buffers seem to be largely for appearance but oval buffers give that bit of extra clearance over round ones of a similar maximum width.  Buffer centre lines are nominally  5 1/2"  above steam age maximum permitted platform heights  ( 3ft)     The big buffers seem quite logically most common where pushing is expected,  Auto trains, Banking etc.  You would expect GWR KIngs to need oval buffers with their long front overhang, but they didn't yet the LMS Pacifics did.  Then again the Princess looks more impressive with their ovals than the A3s etc with round and or round with a bit clipped off.

 

[icn]

On 12/09/2022 at 16:33, Steadfast said:

True enough!

Though the 67s that worked previously on Chiltern don't, and it looks like the vast majority of mixed traffic locos on the continent have full rectangles too. Strange one, presumably specced by Beacon on purchase. 

 

Jo

Trapezoidal buffers seem to be standard for Eurolight, I suspect they just kept the default for the UK.

 

// EDIT: in fact they seem to have been standard already in the days of the Vossloh Euro which predates the Eurolight.

Edited September 18, 2022 by icn

[rogerzilla]

Class 47s always appear to have very big round buffers.

[ejstubbs]

On 10/09/2022 at 15:01, icn said:

the oldest trapezoidal version I've found might be this train from 1971 although its unclear whether it had those buffers at time of construction (I suspect they did since I can't find any photos with other buffers): https://de.wikipedia.org/wiki/Doppelstockwagen#/media/Datei:Bf_Rochlitz,_Doppelstockgliederzug.jpg

 

Strictly speaking, those buffers aren't trapezoidal, since they have five sides.  A trapezium or trapezoid is a quadrilateral (confusingly, the two words mean slightly different things according to which side of the Atlantic you are on - but they both mean a four-sided figure, regardless of where you are).

 

Edited September 18, 2022 by ejstubbs