Green Railways — Set 3

Correct Answer: C. Drones

• **Drones** = unmanned aerial vehicles (UAVs) equipped with high-resolution cameras and LiDAR sensors that can survey long stretches of track, bridges, embankments, and retaining walls in a fraction of the time required for foot patrols, transmitting real-time imagery to control centres for analysis. • **Green and efficiency benefit** — drone-based inspection reduces the carbon footprint of track patrolling by replacing diesel-powered patrol vehicles and motorised trolleys; Indian Railways has deployed indigenously developed drones under its 'Drone Drishti' programme for bridge inspection in hilly and flood-prone zones. • AI-powered drone analysis can detect track geometry defects, weld cracks, and vegetation encroachment automatically, enabling predictive maintenance and reducing accident risks without sending humans into hazardous locations. • 💡 Option A (Radio Waves) is wrong because radio-wave-based technologies like ground-penetrating radar are used underground for track-bed analysis, not for aerial monitoring of surface track conditions and bridge structures; Option B (Satellite Imaging) is wrong because commercial satellite resolution is insufficient for detecting millimetre-scale rail defects, and revisit times of days or weeks are too slow for safety-critical monitoring; Option D (Laser sensors) is wrong because track-mounted laser profilometers measure rail geometry from within a moving inspection vehicle, not through aerial surveillance of the kind described in this question.

Correct Answer: D. They are lighter and more energy-efficient

• **They are lighter and more energy-efficient** = an aluminium coach weighs approximately 38–40 tonnes compared to 45–50 tonnes for a comparable stainless steel coach; this 15–20% weight reduction directly lowers the tractive effort needed from the locomotive, translating to 10–15% less electricity or diesel consumption per trip. • **Recyclability advantage** — aluminium retains 95% of its embodied energy value when recycled at end-of-life, and the recycling process consumes only 5% of the energy needed to smelt virgin aluminium; this gives aluminium coaches a dramatically lower lifecycle carbon footprint than steel. • The Vande Bharat Express trainsets use an aluminium shell body monocoque design that contributes to their high acceleration rates and energy efficiency, demonstrating the practical advantage of this material on Indian Railways. • 💡 Option A (They are cheaper) is wrong because aluminium is currently more expensive than steel per tonne, making initial manufacturing costs higher even though operational savings recover the difference over the coach's life; Option B (They are easier to paint) is wrong because aluminium requires special surface treatment before painting and is arguably more complex to coat than steel; Option C (They never rust) is wrong because while aluminium forms a protective oxide layer that resists corrosion, this is a secondary property; the primary sustainability benefit for railways is the weight and energy efficiency, not corrosion resistance alone.

Correct Answer: A. Recycling of PET bottles

• **Recycling of PET bottles** = Plastic Bottle Crushing Machines (also called Reverse Vending Machines or RVMs) installed at major railway stations compact empty PET (polyethylene terephthalate) bottles to one-tenth of their original volume, making them easy to collect and transport to recycling facilities that convert the material into polyester fibre for clothing, bags, and packaging. • **Incentive mechanism** — many RVMs at stations like New Delhi, Mumbai CST, and Bengaluru dispense a small prepaid mobile recharge (typically ₹5–10) or discount coupon in exchange for each bottle inserted, creating a direct financial motivation for passengers to recycle rather than litter. • Indian Railways generates an estimated 55,000 tonnes of plastic waste per year at stations; RVMs target the single-use beverage bottle category, which is the most visible and voluminous component of this waste stream. • 💡 Option B (Plastic manufacturing) is wrong because crushing machines reduce and collect plastic for recycling, not for manufacturing new plastic products on-site; Option C (Water sales) is wrong because the machines process empty discarded bottles and have no connection to water vending operations at platforms; Option D (Waste burning) is wrong because burning PET plastic releases toxic dioxins and furans, which is prohibited under environmental law and is the very practice that recycling is designed to replace.

Correct Answer: C. Environment-friendly projects

• **Environment-friendly projects** = the green ribbon or green colour coding on Indian Railways' project branding and communications marks initiatives that have a documented positive environmental outcome, such as solar installations, bio-toilet fitments, LED conversions, and tree-plantation drives, distinguishing them from purely infrastructure or commercial projects. • **Mission 41K link** — Mission 41K is Indian Railways' programme to achieve ₹41,000 crore in cumulative energy savings by adopting renewable energy, LED lighting, HOG, and regenerative braking; the green ribbon branding reinforces the railway's public commitment to this target. • Green branding also helps railway zones compete internally for sustainability accolades and attracts CSR partnerships from private companies seeking to associate with credible environmental initiatives. • 💡 Option A (High speed) is wrong because high-speed rail projects use a different branding category focused on speed and capacity, not ecological impact; Option B (New construction) is wrong because new line or station construction projects are marked by milestone boards and project identifiers unrelated to green ribbon eco-labelling; Option D (Safety first) is wrong because railway safety messaging uses specific yellow and red colour codes and signage under a separate safety programme, not the green ribbon system.

Correct Answer: C. Vijayawada

• **Vijayawada Junction** = the first Indian railway station to receive the IGBC Gold rating, recognised for adopting a comprehensive package of green measures including a rooftop solar plant, 100% LED lighting, rainwater harvesting, organic waste composting, and extensive tree plantation across the station campus. • **Vijayawada's green credentials** — it falls under South Central Railway and handles one of the highest passenger volumes in Andhra Pradesh; achieving Gold rating here demonstrated that even high-traffic stations can meet stringent eco-standards without compromising operational efficiency. • The IGBC Gold rating requires a station to score 60–75 points across energy, water, materials, indoor environment, and innovation categories; Vijayawada's early adoption inspired a wave of green station upgrades across South India. • 💡 Option A (Secunderabad) is wrong because Secunderabad received the Platinum rating (the highest tier), not the Gold rating that this question specifically asks about; Option B (Jaipur) is wrong because Jaipur Junction is known for its heritage-inspired renovated façade and is on the Rajasthan state tourism circuit, but was not the first IGBC Gold station; Option D (Kolkata) is wrong because Howrah and Kolkata stations are under Eastern Railway and received their IGBC ratings at different times and tiers than Vijayawada.

Correct Answer: A. Use of suction with bio-digesters

• **Use of suction with bio-digesters** = Bio-Vacuum toilets combine the airline-style vacuum flush mechanism (which uses compressed air suction requiring only 0.2–0.5 litres of water per flush) with an underslung bio-digester tank on the coach, where DRDO-developed anaerobic bacteria biologically decompose the collected waste into innocuous effluent. • **Water savings** — standard bio-toilets use 1–1.5 litres per flush; bio-vacuum technology cuts this to below 0.5 litres, a reduction of over 70%, which is critical on long-distance trains where fresh water supply is limited and tank-refilling at stations is operationally constrained. • Indian Railways began testing bio-vacuum toilets on Tejas Express and select Rajdhani rakes as a step toward fully autonomous waste management in premium trains with no discharge at any point in the journey. • 💡 Option B (Waterless cleaning) is wrong because completely waterless toilet technology suitable for high-use passenger trains does not yet exist at railway scale; even vacuum systems require a small quantity of water for the seal and bowl rinse; Option C (Manual cleaning) is wrong because manual cleaning is labour-intensive and not a technology at all, merely a traditional practice that bio-vacuum replaces; Option D (Chemical dissolving) is wrong because chemical toilets use formaldehyde or blue-dye disinfectants to mask and hold waste without biological decomposition, which is fundamentally different from the bio-digester mechanism.

Correct Answer: D. Moving the trains

• **Moving the trains** = traction power (also called traction energy) is the electricity drawn from the 25 kV overhead catenary system by electric locomotives to power their traction motors, which turn the driving wheels and propel the entire train load — it accounts for about 75–80% of Indian Railways' total electrical energy consumption. • **Scale of consumption** — Indian Railways consumes approximately 18,000 million kWh of electricity annually for traction alone, making it one of the top five largest single electricity consumers in India; transitioning this traction load to renewable sources is the most impactful single action for achieving Net Zero. • Under its renewable energy procurement plan, Indian Railways is signing long-term Power Purchase Agreements (PPAs) with wind and solar developers to supply traction energy at fixed tariffs below the grid rate, achieving both green and cost goals simultaneously. • 💡 Option A (Lighting at stations) is wrong because station lighting is classed as 'non-traction' or 'general services' load, which though significant accounts for only about 20–25% of total railway electricity use; Option B (Operating lifts) is wrong because escalators and lifts at stations are a tiny sub-category of non-traction auxiliary load and are not what the specific term 'traction power' refers to; Option C (Booking tickets) is wrong because ticketing uses computers and network equipment that draw negligible power compared to locomotive traction, and is classified as IT or administrative energy, not traction energy.

Correct Answer: A. Mechanized cleaning

• **Mechanized cleaning** = a system in which trained teams use motorised scrubber-dryers, jet-pressure washing machines, and vacuum-suction trolleys to clean platforms, concourses, and toilets; these machines consume far less water (high-pressure jets use water at 70–100 bar, cleaning effectively with minimal volume) and eliminate the need for large quantities of chemical detergents. • **OBHS and station cleaning** — under the On-Board Housekeeping Service (OBHS) and Integrated Station Cleaning contracts, mechanized cleaning is mandatory at all A1 and A category stations; performance is monitored through third-party audits and passenger feedback on the Rail Madad app. • Mechanized cleaning machines can reduce water consumption per 1,000 sq metres of floor area by up to 60% compared to manual mopping with buckets, aligning directly with Indian Railways' water conservation mandates. • 💡 Option B (Manual sweeping) is wrong because manual sweeping is the conventional method that mechanized cleaning replaces; it is labour-intensive, less effective at removing embedded dirt, and not a 'green' innovation; Option C (Using acid only) is wrong because acid cleaning (muriatic acid for toilets) is a harsh chemical approach that damages surfaces, produces fumes, and is harmful to workers and waterways; Option D (Cleaning once a week) is wrong because infrequent cleaning leads to pest infestation and disease risk, especially in high-footfall stations, and contradicts railway's Swachh Bharat commitments.

Correct Answer: C. Reduce daytime electricity use

• **Reduce daytime electricity use** = Natural Day-lighting Pipes (also called solar light tubes or tubular skylights) are hollow, highly reflective aluminium tubes fitted with a dome on the roof that capture and direct sunlight down into large enclosed spaces like railway workshops, goods sheds, and station waiting halls, providing daylight-quality illumination without any electricity. • **Energy and cost savings** — a single 530 mm diameter light tube can illuminate an area equivalent to 5–6 standard tube lights during peak daylight hours; Indian Railways has deployed these across workshops in Perambur, Lallaguda, and Parel, reducing daytime lighting electricity bills to near zero in those areas. • These pipes also improve worker productivity and reduce eye strain because natural light closely matches the human eye's optimal spectral response, unlike fluorescent workshop lighting. • 💡 Option A (Prevent leaks) is wrong because the pipes are sealed and water-tight by design but their purpose is light transmission, not leak prevention; waterproofing is a secondary engineering feature, not the reason for installation; Option B (Ventilate the area) is wrong because natural ventilation in railway workshops is achieved through ridge vents, louvres, and cross-flow openings, not light-pipe tubes; Option D (Protect from rain) is wrong because rain protection is addressed by the workshop roof structure itself, and light pipes are mounted on the roof with weatherproof domes, not installed as a weather-exclusion device.

Correct Answer: A. Aesthetics and air purification

• **Aesthetics and air purification** = vertical gardens (also called green walls or living walls) installed on station pillars, boundary walls, and concourse columns carry a dense mat of plants that simultaneously beautify bare concrete surfaces and function as natural air filters, absorbing carbon dioxide, particulate matter, and volatile organic compounds from the station environment. • **Temperature reduction** — the transpiration of water through plant leaves (evapotranspiration) cools the immediate surrounding air by 3–5°C, reducing the urban heat island effect around busy stations and lowering the air-conditioning load inside station buildings. • Bengaluru City Junction and Hazrat Nizamuddin station in Delhi have notable vertical garden installations that have been cited in IGBC assessments as contributing to higher green scores for those stations. • 💡 Option B (Structural strength) is wrong because vertical gardens are lightweight modular panels attached to existing structural elements and add negligible load; they contribute no tensile or compressive strength to the pillar or wall; Option C (Growing vegetables) is wrong because station vertical gardens use ornamental or air-purifying plant species (pothos, spider plants, peace lilies) chosen for aesthetics and hardiness, not edible crop production; Option D (Blocking advertisements) is wrong because advertising hoardings at stations are managed under separate commercial contracts and vertical gardens are placed on non-commercial structural surfaces, not as a deliberate anti-advertising measure.