Pakistani train crashes; 15 dead+

[Energon]

Energon,

Before I answer your question, tell me about your background with the railways and your knowledge about railroads, so that I can respond to your inquiry apppropriately.

I'm not an engineer. My knowledge of railroad technology is limited to open source documents and basic principles of physics.

 

[MastanKhan]

Hi,

If your knowledge is based upon basic knowledge of physics, then you should not have any problems understanding it.

You know each rail tie is about 15 to 20 yds long, maybe less. When you installed the ties on the wooden or concrete sleepers, there is a gap of about a 1/4 inch between the ties, which is left as an expansion joint.

If I remeber correctly, pakistan railways in the late 60's decided to weld the joints on the advice of the americans to reduce the wear and tear and stresses on the wheels of the trains. I believe that the track between lahore and karachi was completely done by the mid 70's. Now don't get me wrong, all the track is not one piece for 600 miles. After every few miles I think 5 to 8 miles, a couple of ties are left un-welded for heat expansion of the rails.

So, if the joint is welded every 20 yds, and there are about close to 90 ties in a mile, that would mean that a wheel would hit that 1/4 inch gap 90 times in one mile---that is where you get that sound of klickety klack---and every time the wheel hit that spot, naturally there will be wear and tear of the wheel at every spot it hit the gap----now compare hitting the spot 450 times in five miles to hitting it 2 or 3 times in the same distance---obviously the tear would be 200 times less on the wheel than otherwise.

So, next time you are travelling on the train, notice how silent the track is once the train gets on the straight track after it has left the web of exchange and interconnecting tracks. Also look for the welding spot on the side of the rail links when you are at the rail staion.

 

[Energon]

Thanks for the info Mastan.

Although I can certainly see what the intention of doing this was, I'm a bit perturbed by it's implications. The temperature, atmospheric conditions and the resultant seasonal variations are very unique on the subcontinent.

The summers are incredibly hot, but there are also periods of heavy rains which I'm sure affects the tracks as do the cool if not cold winters. I'm surprised that there aren't more regular gaps left to accommodate the changes in the tracks. Also, if the segments are being fused for such large distances on tracks that aren't straight all the way through (they have to curve in multiple places) resulting in a non linear expansion/contraction, I'm guessing that there's a lot of resultant strain on the welded joints.

There's no doubt that there are major temperature variations in the USA as well... but it seems to me that the level of technology used to maintain the tracks in addition to all the sensors aboard the trains themselves prevents from possible mishaps of this nature. I don't think the rail networks in developing nations have such a backup system.

Again, since I don't have an engineering background maybe I'm blowing this whole thing out of proportion... but it just seems very odd and dangerous to me as a layperson that the joints on a rails in a country with significant variations in temperature are being welded for such long stretches.

 

[MastanKhan]

Energon,

I just laid out the basic principal of welding the joints. The welds could be at a longer distance or at a shorter distance, according to the need---but where the accident took place, it is not absolutely freezing cold---so I don't understand why that statement was made by the railway official---it could be related to a defected weld----if that is the case then I am pretty sure that speed was also a factor.

These diesel locomotive engineers are like cowboys, on that track, if there was no caution sign, he might have been flying full throttle close to a 90 mph. Full htrottle is about 110--120. I came across one driver---he claimed 110 mph between hyderabad and karachi section and that was in I believe 1977. According to him---that was the most solid track in the country, with very hard ground under the track.

If the track breaks under the train load because of speed, it is an instantaneous disaster and no sensor will be helpfull.

Other things might also pop out after the initial inquiry is completed.

 

[HAIDER]

Sir Mastan in primiliary investigation, driver said he was driving at 105, usual speed is 120 kph

NAUSHAHRO FEROZE, Dec 20: The Pakistan Railways said on Thursday that while investigation was still under way, sabotage did not appear to be the cause of derailment of the Karachi Express which, according to the revised figures, killed at least 40 people and injured 249 others on Wednesday night.

An FIR lodged by the guard of the train and statements of some officials and passengers initially indicated that a fault in rail track might have caused the accident.

“The real cause has not been ascertained yet,” said Pakistan Railways’ operations manager Junaid Qureshi.

The FIR has been lodged under Sections 337-G, 320, 427 of the PPC and Section 129 of the Railways Act. The police told Dawn that guard Ghulam Shabbir Chandio had stated in the FIR that the accident had taken place due to the train’s jerk.

The train driver told police that the train was running at normal speed of 105-kph when the accident took place.

 

[MastanKhan]

Haider,

I can just just narrate my experience. Quite a few times I sat on the 3rd seat of the diesel locomotive from rohri to karachi on the night trains, between 1975 and 1977. The locomotive on the express trains was type GMU 30. The railway got those engines from the u s in 72 or 74 and they could haul some ***. Even though it had a speed governor, which was conveniently removed, 65 mph was never the option in my experience, it was more towards the mid 70's and 80's mph. I cannot second guess the driver, he maybe right, maybe it was caused by the train that had gone ahead of it, a faster train, could have caught a dip on the track, caused a stress fracture of the weld, track went out of alignment and the jerk could have been caused when the engine broke free of the coaches of karachi express---there are so many different things that could have caused the accident, but they are all very closely related. The diesel locomotive is close to 100 tonnes, then each coach is around 40 to 45 tonnes, around 14 to 16 coaches because of eid rush--a lot of tonnage---so 65 mph is not slow speed either.

Other accidents that have happened before were between multiple trains. This is a unique circumstance----one train only.

 

[Tiki Tam Tam]

These links may help:

TTCI searching for improved in-track welding methods - Brief Article | Railway Track and Structures | Find Articles at BNET.com

Wide-gap welds offer railroads potential savings | Railway Track and Structures | Find Articles at BNET.com

Railway Technology - Schlatter - Rail Welding Technology

And the most comprehensive one:

LR55 tramway and railway track system frequently asked questions

And it not the rails alone that can be responsible for the accidents. Defective wheels or coaches also can lead to accidents.

 

[Cheetah786]

Human life have no value in our countries once some one is held responsible for these accidents and have to pay with what they love the most ''Money'' most these accidents will be far and few.
It dont matter what kind of weld is there or not bottom line is nothing will come out of it.they will lay down the tracks same way it was done before no improvements will be made cause no one will be held responsible.

 

[MastanKhan]

Hi,

As Salim mentioned, there may be other reasons for the accident---as the germans found out---with their high speed train a few yearsago.

Even with a welded track and an extra high quality suspension system and noise reducing options, the german riders were not satisfied with the noise level of their high speed pride, they wanted german ingenuity to come up with a quiter ride. And indeed it did.

Around the steel wheel, they mounted a rubber ring and on top of that they mounted the steel rim. There were skeptics who thought that it would never work. The german engineers made it work. Somehow it passed the german safety inspection and the wheels got mounted on the coaches.

All went well till one day, the high speed train is on its run, it is going to pass under an over head bridge, which has concrete pillars next to the rail track, the train passes a connection transition, for some reason the track shift is not complete and it stays partially open, if I am not forgetting it, the wheel got of the track, the train is still moving at a high speed, the passengers feel a slight bump, the conductor pays no attention to a customers complaint, and then suddenly the piece of broken ring proturdes the coach, the coach shakes, the wheel breaks of, the coach jerks of the track and hits the pillar post, the impact breaks it away from the locomotive, the locomotive driver does not know if the train has broken loose. As the coach hits the concrete pillars, it crumbles, the coaches behind it slam into it one after the other It is total chaos, death, destruction and mayhem.

If the wheel had broken another 50 yards further---there would not have been as much destruction and loss of life as that coach would have passed the concrete pillar.

 

[IceCold]

Heavy Chinese engines caused Mehrabpur accident: report

By Imtiaz Hussain

KHAIRPUR: The railway authorities have issued suspension orders of seven officials in connection with the recent derailment of the Karachi Express at Mehrabpur.

The News learnt on Tuesday that the General Manager Pakistan Railways had initially suspended the divisional superintendent, Railways, Karachi, a divisional engineer, assistant engineer, PWI and three other officials after a probe committee declared them responsible for the Karachi Express derailment that claimed more than 80 lives and injured 200 other passengers.

Railways sources revealed to this correspondent that Pakistan had imported locomotives from China weighing 23.6 tonnes – three times heavier than the engines plying on the railway tracks in the country.

These engines were of Group 4 status, which could not be allowed to travel on a single-line track. The sources said that the railway line from Karachi to Tando Adam was being especially repaired for the Chinese engines but despite being aware of the technical problems, the railway authorities decided to run these heavy engines on the very same track.

The sources further told The News that the railway line, which was too old to even bear the strain of running low-weight engines, was technically not fit for the heavy Chinese engines of Group 4.

However, the authorities, in what appears to be a gross act of negligence, put the lives of hundreds of passengers at risk and allowed the imported engines to ply on the track that needed a complete overhaul.

Sources also revealed that initially the enquiry committee was of the view that the cause of the derailment of the Karachi Express was the cracks in the line. However, the GM Railways, after receiving initial reports, suspended the officials responsible for gross negligence. The FGIR team of Pakistan Railways has yet to complete the investigation and will examine the Mehrabpur and Rohri stations and it is expected that many more railway officials will be suspended in the near future.

 

[IceCold]

Heavy Chinese engines caused Mehrabpur accident: report

By Imtiaz Hussain

KHAIRPUR: The railway authorities have issued suspension orders of seven officials in connection with the recent derailment of the Karachi Express at Mehrabpur.

So atleast some steps are taken but i doubt the suspened officials would include any high level.