Bridges & Tunnels — Set 2

Correct Answer: C. Konkan Railway

• **Konkan Railway** = The Konkan Railway Corporation Limited (KRCL) manages the 756-km coastal route from Roha (Maharashtra) to Thokur (Karnataka) and holds the record for the maximum number of tunnels and bridges per km of any Indian railway zone — 91 tunnels totalling over 82 km and more than 2,000 bridges. • **Scale of engineering** — At the time of its inauguration in 1998, the Karbude Tunnel (6.5 km) was the longest railway tunnel in India, and the Panval Nadi Viaduct was the highest bridge in Asia; both were milestones driven by Konkan's rugged terrain. • Konkan Railway pioneered the use of computerised interlocking signalling and slip-form construction techniques in India. • 💡 Option A (Western Railway) is wrong because it covers the relatively flat Mumbai–Gujarat–Rajasthan belt with far fewer tunnels; Option B (Southern Railway) is wrong because while it has coastal terrain, it does not match Konkan in density of tunnels; Option D (North Frontier Railway) is wrong because although it has challenging terrain in the Northeast, it does not have 91 tunnels on a single corridor.

Correct Answer: D. 1962

• **1962** = The Saraighat Bridge was inaugurated on 27 April 1962 by Prime Minister Jawaharlal Nehru, becoming the first bridge ever built across the Brahmaputra River. It is a rail-cum-road bridge connecting the north and south banks of the river at Guwahati. • **Historical site** — The bridge was built near the site of the 1671 Battle of Saraighat, where Ahom Admiral Lachit Borphukan defeated the Mughal fleet under Ram Singh I, one of the most celebrated naval battles in Indian history. • For 25 years (1962–1987), the Saraighat Bridge was the only crossing over the Brahmaputra in Assam; a parallel road bridge was added later to ease congestion. • 💡 Option A (1952) is wrong because India was still in the First Five-Year Plan period and the bridge was not built then; Option B (1982) is wrong because by that year the Saraighat Bridge had already been operational for two decades; Option C (1972) is wrong because the bridge had been inaugurated a full decade earlier, in 1962.

Correct Answer: D. Kolkata

• **Kolkata** = India's first underwater metro tunnel is part of the Kolkata Metro's East-West corridor (Line 2), which passes beneath the Hooghly River between Howrah Maidan and Esplanade stations. It is the first time in India that a metro tunnel was bored under a live river. • **Technical detail** — The tunnel runs 13 metres below the river bed at its deepest point; two parallel tubes of 5.74-metre diameter were bored using Earth Pressure Balance (EPB) tunnel boring machines. The section was inaugurated in March 2024. • The East-West Metro corridor stretches 16.6 km from Howrah Maidan to Sector V (Salt Lake), linking the two major urban centres across the Hooghly. • 💡 Option A (Mumbai) is wrong because Mumbai's coastal and river crossings are by surface or elevated rail, not underwater metro tunnels; Option B (Chennai) is wrong because Chennai Metro has no underwater river tunnel in its current network; Option C (Kochi) is wrong because Kochi Metro runs on elevated viaducts over the Vembanad Lake, not underground under a river.

Correct Answer: A. Old Godavari Bridge

• **Old Godavari Bridge** = The Old Godavari Bridge at Rajahmundry, also known as the Havelock Bridge (after Viceroy Lord Havelock), was commissioned in 1900 as the first rail bridge over the Godavari River. It facilitated the critical Chennai–Howrah main line for nearly a century before being decommissioned in 1997. • **Replacement** — A new bowstring-arch girder bridge (the Second Godavari Bridge) with 28 unique arch spans was built parallel to it. The old structure has since been preserved as a heritage pedestrian walkway in Rajahmundry. • The Godavari Bridge crossing at Rajahmundry is one of the most strategic points on the South–East Coast Railway network. • 💡 Option B (Fourth Godavari Bridge) is wrong because no bridge by that exact designation is associated with the historic Havelock name; Option C (Prakasam Barrage) is wrong because it is a road and irrigation barrage over the Krishna River, not the Godavari; Option D (Dowleswaram Barrage) is wrong because it is a weir across the Godavari near Eluru used for irrigation, not a railway bridge.

Correct Answer: C. Son

• **Son River** = The Nehru Setu (Nehru Bridge) spans the Son River in Bihar, connecting Dehri-on-Son on the western bank with Son Nagar on the eastern bank. At 3.06 km with 93 spans, it held the title of India's longest railway bridge for several decades until the Vembanad Rail Bridge surpassed it. • **Historical note** — The bridge was named after India's first Prime Minister Jawaharlal Nehru and lies on the East Central Railway zone; it is a critical link on the Howrah–Delhi Grand Chord route. • The Son River is a major right-bank tributary of the Ganges, originating in Madhya Pradesh, which makes crossing it at this point essential for north-south rail connectivity in Bihar. • 💡 Option A (Gandak) is wrong because the Gandak River is a smaller Bihar tributary and Nehru Setu does not cross it; Option B (Kosi) is wrong because the Kosi flows further east in Bihar near the Nepal border; Option D (Ganges) is wrong because the main Ganges crossing at Patna is a separate structure (J.P. Setu / Digha-Sonpur Bridge).

Correct Answer: A. Manipur

• **Manipur** = The Noney (Ijai) Bridge under construction in Manipur's Noney district is set to become the world's tallest railway pier bridge with a pier height of 141 metres, surpassing the Mala-Rijeka Viaduct (139 m) in Montenegro. It is a key structure on the Jiribam–Imphal rail line. • **Specs** — The total bridge length is about 703 metres; the pier height of 141 m equals roughly a 47-storey building. It is designed to survive Zone-V (maximum-intensity) seismic activity common in Northeast India. • The Jiribam–Imphal project (111 km) will bring the Manipur capital Imphal onto the Indian broad-gauge railway map for the first time, passing through 12 major bridges and 10 tunnels. • 💡 Option B (Nagaland) is wrong because the Jiribam-Imphal line runs through Manipur, not Nagaland; Option C (Meghalaya) is wrong because no record-breaking pier bridge is under construction in Meghalaya; Option D (Mizoram) is wrong because Mizoram's rail project (Bairabi–Sairang) has high bridges but none targeting the world pier-height record.

Correct Answer: A. Digha-Sonpur Bridge

• **Digha-Sonpur Bridge (J.P. Setu)** = At 4.556 km, the Digha-Sonpur Bridge — officially named J.P. Setu after Jayaprakash Narayan — is the longest rail-cum-road bridge over the Ganges. It connects Digha Ghat in Patna (south bank) with Sonpur (north bank) in Bihar, opened in 2016. • **Traffic impact** — Before J.P. Setu, travellers between Patna and Hajipur/Muzaffarpur had to cross via the 5.6-km Mahatma Gandhi Setu road bridge (often congested) or take a longer train route; J.P. Setu cut travel time by over an hour. • The bridge carries a double-line broad-gauge railway on the lower deck and a four-lane highway on the upper deck, making it a true dual-mode crossing. • 💡 Option B (Munger Ganga Bridge) is wrong because it is shorter and a road-cum-rail bridge downstream near Munger, not the longest over the Ganges; Option C (Vikramshila Setu) is wrong because it is a 4.7-km road bridge between Bhagalpur and Naugachia, with no rail deck; Option D (Mahatma Gandhi Setu) is wrong because it is a road-only bridge (5.6 km) at Patna–Hajipur with no rail component.

Correct Answer: C. Varanasi

• **Varanasi** = The Malviya Bridge (originally Dufferin Bridge) is a double-decker rail-cum-road bridge over the Ganges at Varanasi, Uttar Pradesh. Opened in 1887, it was named after Viceroy Lord Dufferin and renamed Malviya Bridge after independence in honour of Madan Mohan Malaviya, founder of BHU. • **Structure** — The bridge is 1,059 metres long with 11 spans; the lower deck carries broad-gauge railway track (on the Varanasi–Mughalsarai section) and the upper deck carries a two-lane road. It is one of the oldest functioning rail bridges in India. • The bridge is a key junction point between the Northern Railway and North Eastern Railway zones and serves as a critical supply artery for the holy city of Varanasi. • 💡 Option A (Patna) is wrong because the Ganges bridge at Patna is J.P. Setu / Mahatma Gandhi Setu, not the Dufferin/Malviya Bridge; Option B (Prayagraj) is wrong because Prayagraj's historic rail bridge is the Curzon Bridge; Option D (Lucknow) is wrong because Lucknow sits on the Gomti River and has no Ganges crossing.

Correct Answer: D. Pernem Tunnel

• **Pernem Tunnel** = The Pernem Tunnel in Goa is notorious as the most difficult tunnel on the Konkan Railway to construct, due to extremely soft, laterite-rich and water-logged soil that caused multiple collapses during boring. It was among the final obstacles cleared before Konkan Railway achieved full operational status in 1998. • **Engineering response** — Engineers used ground freezing and chemical grouting techniques to stabilise the saturated soil; sections of tunnel had to be rebuilt multiple times, significantly delaying the overall project schedule. • The Konkan Railway passes through Goa via 12 tunnels; the Pernem Tunnel is the most westerly and the closest to the coast, which explains its water-logged geology. • 💡 Option A (Karbude Tunnel) is wrong because the Karbude Tunnel near Ratnagiri, Maharashtra, is the longest on Konkan Railway but was not infamous for soil collapses; Option B (Old Goa Tunnel) is wrong because no tunnel by that specific name is associated with the most difficult Konkan construction; Option C (Nivasar Tunnel) is wrong because the Nivasar Tunnel in Maharashtra did not face repeated soil collapse issues during construction.

Correct Answer: D. Bowstring Girders

• **Bowstring Girders** = The Second Godavari Bridge (Arch Bridge) at Rajahmundry, Andhra Pradesh, is distinguished by its 28 bowstring-arch girder spans — a design where a horizontal beam (string) holds the arch in compression, eliminating the need for large abutments. It is one of the longest bowstring-girder bridges in Asia at approximately 2.73 km. • **Replacement** — It replaced the century-old Havelock Bridge (Old Godavari Bridge, 1900) and carries rail traffic on the Howrah–Chennai main line; the old Havelock Bridge is now preserved as a pedestrian walkway. • Bowstring girder bridges are rare because they require precise pre-stressing of steel cables; the Godavari bridge's 28 identical spans made their uniform construction a significant engineering feat. • 💡 Option A (Suspension cables) is wrong because suspension bridges hang a deck from overhead cables anchored at towers, a completely different structure; Option B (Cantilever Spans) is wrong because cantilever bridges project out from piers without continuous arches, unlike the Godavari's bowstring design; Option C (Truss Girders) is wrong because truss girders form triangulated frameworks, not the characteristic arch-and-string profile of the Second Godavari Bridge.