Buffer stop collision in Richmond, Sydney injures 16

Posted about an hour ago in the Sydney Morning Herald are details of the preliminary investigation, indicating an approach speed of 35 km/h.

www.smh.com.au/national/nsw/sydney-train-travelling-at-35km-h-moments-before-hitting-safety-buffer-20180308-p4z3f4.html

I've had a look for the existing thread, I can't see it anywhere (and a search for "Richmond" gives lots of irrelevant answers), if someone can provide a link then we'll happily merge/unlock.

Thanks kesmet, Threads merged/unlocked

I've not read the report yet, but AIUI all UK stock running on the mainline, other than tube stock, has the same buffer height (since 1887 the standard for goods wagons at least has been "roughly a foot in diameter with centres about five foot eight inches apart and three foot four inches above rail height") so that issue wouldn't arise - or at least not in the same way. The issue in the UK is differing deigns of coupling/buffers/anti-climbers and their relative prominence - most buffer stops are designed for impacts from traditional buffers slightly outside the rails, but often modern coupler designs negate the need for buffers and so an initial impact with a buffer stop occurs centrally between the rails.

Compare for example buffer stops on the DLR with traditional buffer stops

Yes, there was, but it's also worth considering that the reasons for providing buffer stops have changed through the years.

In railway terms, 'buffing' is a compressive force between vehicles (and fixed objects). Buffers on vehicles act to absorb the compressive forces between them.

Buffer stops act to engage with the buffers on the train at the end of a piece of track for the train to buff against; they were only designed for very low speed compression and certainly not for any high-speed impact. The traditional way of managing a higher speed approach to a dead-end was to either install hydraulic buffers which provided a controlled buffing force until they were fully compressed, or install a sand drag (or more accuratley a sand hump) which would give a degree of retardation prior to ultimate derailment or collision with the buffer stop.

The Moorgate collision (amongst others) demonstrated that sand drags weren't actually that effective and this lead to a series of trails where (unstaffed) trains were driven into a series of materials which were considered to have good retarding properties - this lead to the design of train arrestor we have today at Edgware which is designed to provide controlled retardation at or below a specific speed. However, ealrier than this (as far back as 1902), research in Europe (particularly Germany) had developed various designs of friction buffer stop to provide a controlled means of deceleration - usually using additional blocks positioned behind the buffer to provide controlled deceleration and dissipation of the kinetic energy involved.

The modern train arrestor is thus designed to cope with a far higher impact speed than the traditional rail-built buffer stop ever was.

BTW, there used to be some fine (and quite old) examples of this on a couple of mainline platforms at Paddington (11 & 12?). I'm sure I have a picture or two of them but I'm also sure I can't find them a the moment.

There are several around the country and they get tested like this

The on train side of the system is tested both on train prep and by tripckck testers located around the network,

the on track equipment while not actually tested is visible to drivers and it would be quickly noticed if there was a problem with it's operation.

At Chesham, if this fails the signal approaching is put to danger, I have no idea about any other location.