Freight train accident near Doncaster.

[whole diary]

[broadgage]

Early reports state.
Freightliner train was stopped. GBRF train struck rear of the stopped train.
No reports of any injuries. GBRF driver taken to hospital as a precaution but reported unhurt.
The GBRF locomotive rode up onto the rear wagon of the freightliner train and substantially destroyed the container carried thereon. Contents of container scattered around.
Several vehicles derailed and damaged.

I am not familiar with the area, but reports state that the accident is on a freight only line and that the signals may therefore not be TPWS^▸ (Train Protection and Warning System) fitted.

[paul7575]

In fact it is a passenger line.  A relatively small number of trains from the south calling at Doncaster use it.  It also merges into the route taken by passenger trains coming from Lincoln towards Doncaster, so I think TPWS^▸ (Train Protection and Warning System) would have been provided for the route even if passenger trains weren’t planned on the relatively short link between the 2 passenger routes.

[Electric train]

British Transport Police said: "Officers were called to the line in Bessacarr at 6.26am this morning (5 July) following reports of a collision between two freight trains. Minimal delay to passenger trains

[stuving]

If I've picked the right location, it's inside Potteric Carr nature reserve, a wetland area and SSSI. Not ideal for bringing in big cranes, with no roads and an unwillingness to modify the ground temporarily. It may be close enough to the main line for a Kirow to provide enough lift, but that would mean closing the ECML^▸ (East Coast Main Line) for the duration (though there is a single line usable as a bypass). And then there's all that OLE^▸ (Overhead Line Equipment, more often "OHLE") to move out of the way ...

If you are thinking "where have I heard the name Potteric Carr before", it's the name of a whizzy new electronic feed station. That isn't inside the nature reserve, it's next to it by the A6182. AFAICS^▸ (As Far As I Can See) there's a pair of ABB's 50 MW static frequency converters humming quietly to themselves there.

[broadgage]

Drifting a little O/T, I doubt that large frequency converters are installed in the locality. OHLE and the national grid both use 50 cycles. Perhaps large transformers to step down a higher voltage grid supply to 25 kv or to 25/50 kv.

[Electric train]

If you are thinking "where have I heard the name Potteric Carr before", it's the name of a whizzy new electronic feed station. That isn't inside the nature reserve, it's next to it by the A6182. AFAICS^▸ (As Far As I Can See) there's a pair of ABB's 50 MW static frequency converters humming quietly to themselves there.

Drifting a little O/T, I doubt that large frequency converters are installed in the locality. OHLE and the national grid both use 50 cycles. Perhaps large transformers to step down a higher voltage grid supply to 25 kv or to 25/50 kv.

The reason for the SFC is to provide resilience to the 25kV supply in the Doncaster area.  The choice of 33kV 3 phase supply was due to there being no 132kV near by.   

SFC was chosen so that the single phase 25kV load is balanced across the 3-phase supply, also there is a practical limit of 10MW for a 33/25kV transformer.

There are other SFC planned most are 132kV 3-phase to 25kV again to balance the 25kV load across the 3-phase supply   

[paul7575]

Static frequency changer (or converter) is a fairly generic term.  In this rail use they’re more of a 3 phase to single phase conversion device. So you can think of it as a back to back rectifier and inverter, with a very short DC^▸ (Direct Current) link in the middle.  50 Hz > DC > 50 Hz is then a couple of frequency changes.

And of course it has to work backwards to provide regeneration.

[stuving]

Drifting a little O/T, I doubt that large frequency converters are installed in the locality. OHLE and the national grid both use 50 cycles. Perhaps large transformers to step down a higher voltage grid supply to 25 kv or to 25/50 kv.

It's one of those misleading names, isn't it? - given for its original purpose and kept when it's used for something else. Converters were even more important in early electricity supplies, and were motor/generator sets (two machines or one combined one). "Static" just means no rotating machinery.

The main need originally was AC to DC^▸ (Direct Current), but every other possibility has been tried. AC to AC gets called a frequency converter because it could do that, though (as in this case) the frequency may be the same on both sides. German railways do convert frequencies, to produce their 16 2/3 Hz traction supply. SFCs have been in use for over thirty years there, following the same valve/thyristor/GTO/IGBT^▸ (Insulated Gate Bipolar Transistor) technology evolution as trains.

In this case it's converting the phase type of the supply, but the same basic kit has more tricks it can do. Put a big battery on the intermediate DC link, and it can store power for buffering and peak load management. If it's reversible (which I guess the latest ones are) then with a smaller battery it's the kind of "synthetic inertia" being tried out as a way of keeping the grid stable.

[Electric train]

Drifting a little O/T, I doubt that large frequency converters are installed in the locality. OHLE and the national grid both use 50 cycles. Perhaps large transformers to step down a higher voltage grid supply to 25 kv or to 25/50 kv.

It's one of those misleading names, isn't it? - given for its original purpose and kept when it's used for something else. Converters were even more important in early electricity supplies, and were motor/generator sets (two machines or one combined one). "Static" just means no rotating machinery.

The main need originally was AC to DC^▸ (Direct Current), but every other possibility has been tried. AC to AC gets called a frequency converter because it could do that, though (as in this case) the frequency may be the same on both sides. German railways do convert frequencies, to produce their 16 2/3 Hz traction supply. SFCs have been in use for over thirty years there, following the same valve/thyristor/GTO/IGBT^▸ (Insulated Gate Bipolar Transistor) technology evolution as trains.

In this case it's converting the phase type of the supply, but the same basic kit has more tricks it can do. Put a big battery on the intermediate DC link, and it can store power for buffering and peak load management. If it's reversible (which I guess the latest ones are) then with a smaller battery it's the kind of "synthetic inertia" being tried out as a way of keeping the grid stable.

The term static frequency is used as it is not variable frequency.

 The DC section of the device operates at 3kV DC batteries would be a maintenance nightmare, the procedures to maintain this device at Doncaster has occupied some of my time over the last 3 years even more time of some of my colleagues.

The Doncaster SFC is the first 25kV in the UK^▸ (United Kingdom), there are a number of others planned

[stuving]

RAIB^▸ (Rail Accident Investigation Branch) have announced they will be investigating this collision, and have provided their usual short description of what happened. It's very much "how" not, at this stage, "why".

Investigation into a signal passed at danger and subsequent collision between two freight trains near to Loversall Carr junction, Doncaster, 5 July 2022.
Train 4E11 following the collision
At around 06:23 hrs on Tuesday 5 July 2022, train reporting number 4E11, a freight service operated by GB^▸ (Great Britain) Railfreight, collided with the rear of a stationary freight train. The collision took place to the south of Doncaster on the Down Slow/Up West Slow line, between Loversall Carr and Flyover West junctions.

Immediately before the accident, train 4E11 passed signal D197 while it was showing a danger (red) aspect. The rear of the stationary train was approximately 230 metres beyond this signal when the collision occurred.

Train 4E11 was travelling from Felixstowe to Masborough and consisted of 35 container-carrying wagons and a locomotive. It collided with the rear of the stationary train at approximately 28 mph. No-one was hurt in the accident, although the collision derailed a number of wagons in both trains and caused significant damage to the vehicles and infrastructure involved.

Our investigation will seek to identify the sequence of events which led to this incident. It will also consider:

•     the way in which the train was driven
•     any factors which may have influenced the actions of the driver of the train
•     the condition of the signalling system at the time of the incident
•     any underlying management factors.

[stuving]

This RAIB^▸ (Rail Accident Investigation Branch) report was published today. It includes some pictures of the damage that I don't recall seeing before - quite a mess, verging on American.

The conclusion is really that managing tiredness in drivers is never going to be a failure-proof process, even following best practice, and GBRf weren't fully doing that. The driver as implementer of signals remains a single point of failure, unless and until a full train control and protection system exists (and for goods that may never happen).

[Ralph Ayres]

I'm not familiar with the term "American" as a measure of mess! Am I misunderstanding something?

[stuving]

I'm not familiar with the term "American" as a measure of mess! Am I misunderstanding something?

American railways do have a huge network of dodgy track, so they suffer a lot of derailments and level crossing collisions. And since their trains are so long that does usually tip a lot of wagons over before all the momentum is used up. But apart from their number, the classic picture with a row of neatly concertina'd wagons could come from anywhere - even Wales - and Australia has quite a few these days too.

As it happens, the US ones we've seen in the news recently have involved tankers, which adds extra newsworthiness when they carry nasty chemicals or catch fire ... or both.

[Electric train]

This RAIB^▸ (Rail Accident Investigation Branch) report was published today. It includes some pictures of the damage that I don't recall seeing before - quite a mess, verging on American.

The conclusion is really that managing tiredness in drivers is never going to be a failure-proof process, even following best practice, and GBRf weren't fully doing that. The driver as implementer of signals remains a single point of failure, unless and until a full train control and protection system exists (and for goods that may never happen).

TPWS^▸ (Train Protection and Warning System) may have helped I'm sure, but this tends to only be fitted on passenger lines. 

On the scale of USA Railroad crashes this one would be in the minor league, also the US Railroad incidents are often due to mechanical failure like hot boxes or at level (grade) road crossings, they reduce the 'human error' by having a Conductor as well as the Engineer (Driver)