The basic reasons why an engineers’ methodology is workable, but RlyBds’ isn’t
Alignment methodology for building rail lines in Himalayas
Railway Board claimed that construction of the Chenab Bridge will be completed by June, 2018 and the entire rail link will be ready by December, 2018. However, the situation today is that less than half the construction work has been done so far.
Alok Kumar Verma, IRSE (Rtd)
Today one Mr Ajit Kumar @Ajitkum85387448 has asked me this question:
“If the Himalayas are unstable & landslide prone, how will you find stable rock where tunnel construction will be safe?”
I like this question because it goes to the most basic issue: The unique geology of the young Himalayas. The other important underlying point is that just because the Railway Board’s alignment methodology has not worked on the Kashmir project, it does not follow that the methodology which I have proposed will work.
I would slightly enlarge this question to include bridges and cuttings also because the problem with the existing alignment methodology that Railway Board has adopted for building railway lines in the Himalayas has resulted in alignments with massive bridges (like the Chenab Bridge on the Kashmir Rail Link and the Bridge at Noney on the Manipur line), and ultra-high cuttings (like the 150m high cutting at the foundation of the mega arch bridge over Chenab and the huge cutting in the unstable slopes at Sangaldan and Arpinchla in the alignment for the Kashmir Rail Link).
The following are the main requirements for a good alignment for building a railway line in a difficult mountainous terrain:
1. Stability so that landslides and other forms of ground failures will not result in frequent disruptions or cause accidents.
2. Survivability: Ability to withstand the various geohazards, and manmade disasters without excessive damage to the line and disruption to the movement of traffic.
3. Safety: The line will allow safe movement of trains, and if accidents do occur, rapid rescue and relief will be possible.
4. Constructability: Comparable in cost and period of construction with existing lines in similar terrain.
5. Route length: Should be about 1.2 to 1.5 times the straight-line distance covered.
6. Speed and line capacity: Comparable with existing lines in similar terrain.
7. Ease and low cost of operations and maintenance
The geological fact about the Himalayas as these mountains stand today, is that they are composed of highly folded and crushed rock strata. But, on the slopes, the rocks are prone to come down in landslides and other forms of mass wasting because at the surface the rocks tend to be highly weathered from exposure to temperature changes, freezing and thawing, movement of glaciers, rain water and other agents of rock weathering which make the surface rocks weaker than the rocks deeper inside the mountain.
Depth of weathering can be quite high. I am talking of glaciers and freezing and thawing because the weathering that we see today has taken place over millions of years, a long period in which climate has undergone cycles of extreme changes.
Further, the slopes are more susceptible to landslides in the lower reaches near the bottom of the valleys because of presence of deep deposits of slope debris brought down from above.
There are locations on the existing alignments like the location of foundations of Bridge No. 43 and Sangaldan Cutting on the Kashmir Rail Link alignment where the slope debris has been found to be 40 to 60 m deep.
Furthermore, the situation on the slopes gets worse if the rocks are sedimentary and low-grade metamorphic rocks.
Each of the 7 existing alignments for the lines presently under construction and 2 which are under Final Location Survey (Bilaspur-Manali-Leh line and the Chardham lines) have high proportion of the alignments passing through regions of sedimentary and low grade metamorphic rocks and have significant lengths at the lower reaches near to the bottom of the valleys formed by adjacent ridges.
Geological fault lines: The highest risk of damage to the tunnels, bridges and cutting on a railway line is at the geological fault lines. The Himalayas are full of major fault lines. All the 7 alignments have high exposure to the fault lines, particularly the alignment for the Kashmir Rail Link and the Rishikesh-Karanprayag line.
For details of exposure of the Kashmir Rail Link, please read my post on the Sreedharan Committee Report, link to which is given at the end of this thread. Image copy of the report is given in the post. The report also gives a list of the large bridges and tunnels at shallow depth under the slope surface.
Landslides are the most important geohazards, but there are other geohazards which can cause devastating damage to railway lines, often by triggering landslides. These geohazards are earthquakes and deluge by sudden flooding like the recent deluge in Chamoli region in Uttarakhand. At higher altitudes, snow avalanches are another important geohazard.
The Himalayas are known for high seismic activity; studies have shown a high probability of mega earthquake (more than 8 magnitude) striking Himalayas in the next 100 years.
The mega earthquake that last struck Himalayas and its allied ranges is the 8.7 magnitude quake in the North East in 1950 with epicentre in Meghalaya.
This earthquake was so massive that it significantly altered the course of Brahmaputra River.
Several major earthquakes of magnitude more than 6 have struck the Himalayas in the past 20 years, notably the 7.6 magnitude earthquake that struck north-Western Himalayas in 2005 with the worst affected areas in Pakistan occupied Kashmir.
Other major earthquakes have hit Uttarakhand (6.8 magnitude quake in Chamoli 1999, 6.8 magnitude, Uttarkashi in 1991), Nepal (7.8 magnitude in 2015) and the North East states (6.9 magnitude, Shillong in 2011).
Flash floods caused by spells of intense rainfall and other factors, like breaching of an impounded lake, are quite common all over the Himalayas. The most recent devastating floods were in Uttarakhand and Himachal Pradesh in 2013, and the most recent one in Chamoli earlier this month.
I am giving below images of some slides that I used in my presentation to the Ravindra Committee to explain the geohazards in the Himalayas in the region.
The main aim of alignment design and an alignment methodology is to reduce exposure of the would-be line to the various geohazards discussed above. The cause of practically all the problems with the slope-skirting alignment methodology of Railway Board is that it was developed ignoring the high presence of geohazards in the regions where the lines were to be built.
Had these hazards been considered it would have become obvious that most of the tunnels were in weak rocks at shallow depth under the slopes, with significant length along the fault lines.
Similarly, it would have been known that there is a high population of large bridges (span more than 30 m and height more than 50 m above the bottom of the khad/valley) on unstable slopes and many of them are near the fault lines or on thick deposits of slope debris.
Meter Gauge: Another vital factor Rly Bd ignored was that so far only narrow-gauge lines have been built in the Himalayas. Technology has certainly improved in the last 50 years, and it should be possible to build tunnels and bridges for a Broad-Gauge line.
But, the Himalayas population is scanty and there is very limited scope of industry, mining and manufacturing. So, Meter Gauge (MG) is a good option that should have been considered, as there are also many MG lines across the world which give enough throughput to meet the needs.
Because of the steeper gradient (up to 1 in 15), good speed (up to 100 kmph) that an MG line permits, and the smaller size trains; Meter Gauge is inherently more suitable for the challenging terrain of Himalayas than Broad Gauge, notwithstanding some operational constraints which can be managed as being done elsewhere in the world railways.
I have studied this subject, in regards to the alignment for the Bilaspur-Manali-Leh line and my study shows that typically, an MG line in Himalayas will cost about half to 1/3rd the cost of a BG line and handsomely meet the requirements of transportation.
Two Expert Committees have examined the relative merits and demerits of the Railway Board’s alignment methodology vis a vis the new methodology suggested by me. This methodology was developed by me on my own initiative in 2007 based on my experience on the project in 2004-06.
The methodology was later refined with inputs from other engineers who interacted with me in 2007-09, particularly then Member Engineering, Railway Board Mr S. K. Vij.
The Ravindra Committee was prevented from considering change of alignment as the review of alignment in 2007-09 was scuttled by two of the then Members of Railway Board, but the Committee accepted my explanation of the flaws in the existing alignment with the result that it suggested a realignment plan and strategy with steeper gradient of 1 in 60 whose main features were: “taking the line deeper into the mountain, drastically reducing the number and size of bridges and cuttings, and crossing the geological fault lines at close to 90 degrees.”
Another important recommendation was that no construction should take place at the mega arch bridges over Anji and Chenab till a thorough slope stability study is carried out.
But, as I have discussed, “Railway Board’s Debacle in Himalayas”, these recommendations were implemented in a very watered-down manner, and some key recommendations like crossing of the fault lines at close to 90 degrees and building the line as a double line were completely ignored.
Further, no action was taken to change the alignment of the other six Himalayan projects. In fact, till 2015, Railway officials were able to completely conceal the fact from the outside agencies, including both Expert Committees and the Courts that the same alignment methodology had been adopted on six other projects in similar Himalayan terrain.
The Sreedharan Committee examined the alignment that existed in 2014 after it had been realigned in the aftermath of the Ravindra Committee (93 km out of the original 125 km long alignment was changed) and concluded that the alignment should be changed, and the alignment suggested by me should be adopted.
The Committee also said that a double line on my alignment will cost less than what it will take to complete the remaining construction for a single line on the existing alignment.
Railway Board arbitrarily refused to accept the unanimous recommendations of the Committee. Railway Board claimed that construction of the Chenab Bridge will be completed by June, 2018 and the entire rail link will be ready by December, 2018. However, the situation today is that less than half the construction work has been done so far.
In its report, the Sreedharan Committee repeatedly pointed out that the alignment that I have suggested is based on sound principles of science and engineering and proven worldwide practices, including adoption of steep gradient and as straight and as short an alignment as possible for better safety and reduced cost of operation and maintenance.
It is important to note that three of the four Members of the Committee were chosen by Railway Board, only Mr E. Sreedharan was included on the Delhi High Court’s order. It is indeed astonishing that Railway Board questioned competence of the Committee and chose to rely on the claims of the consultants and its own engineers and other officers who had repeatedly bungled the project right from its inception when the alignment was finalised and contracts were awarded ignoring completely the all – important factors of the Himalayan geology.
Even today the Railway Board and its officers keep claiming that all the problems/challenges that they are facing on the project is because of the difficult Himalayan geology. The fact is that they never really addressed the geological factors in the blind hope that as problems arose, they will somehow find technological solutions with the help of foreign consultants.
Both the above-mentioned Expert Committees emphatically said that steep gradient is necessary and desirable as this is a proven practice based on experience of building lines in the various mountain ranges on earth, including the narrow-gauge lines in the Himalayas in India.
Ravindra Committee said that the old rule that catch and slip siding are necessary for steep gradients is obsolete and should be given up.
Further, because my alignment is short and for a double line, only one crossing station is required. The Sreedharan Committee said that even if the Board still insisted on catch and slip siding the same could be easily provided.
Railway Board’s failure on each of the seven projects has shown that in Himalayas the nature’s destructive power (the geohazards) are too strong to be overcome just by technological solutions: “What is needed is a sound understanding of these natural forces and a strategy and solution in the form of a sound alignment that would avoid the hazards and where they cannot be avoided altogether the effects would be minimized.”
Before I conclude, I must say, “The Kashmir Rail Link Project is possibly the Indian Railway project most scrutinized by the statutory authorities of the country. Besides the two Expert Committees, the CAG, PAC, CVC, the Principal Bench of CAT, and Delhi High Court have scrutinised Railway Board’s handling of this project, and all have indicted Railway Board for its mishandling and failure to exercise due diligence in detailed reports / judgements.”
If anyone has any questions, please feel free to ask.
#KashmirRailLink #Himalayas #RailwayBoard #IndianRailway #PMOIndia #PiyushGoyal #NorthernRailway
ALIGNMENT METHODOLOGY FOR BUILDING LINES IN HIMALAYAS: THE BASIC REASONS WHY MY METHODOLOGY IS WORKABLE AND RLY BOARD'S ISN'T
1/8 https://t.co/eLVVj7FEBu pic.twitter.com/s9EJZKkQ6n— Alok Kumar Verma, IRSE (Retd.) (@trains_are_best) February 23, 2021