About Kalka-Shimla Railway (KSR):
- It is a narrow-gauge railway in North India which traverses a mostly mountainous route from Kalka (Haryana) to Shimla (Himachal Pradesh).
- Construction:
- The railway was built in 1898 to connect Shimla, the summer capital of British India, with the rest of the Indian rail system.
- The project’s chief engineer was H. S. Harington.
- The 96 k.m. long, single-track line, often called the toy train line, was opened in 1903.
- It passes through 18 stations, 102 tunnels, and over 850 bridges.
- Total change of altitude: From Kalka (655 meters) to Shimla (2,076 meters).
- The world’s highest multi-arch gallery bridge at Kanoh and the world’s longest tunnel at Barog (at the time of construction) of the KSR were the testimony of the brilliant engineering skills applied to make this railway line.
- It was a UNESCO World Heritage Site in 2008.
- The rail network holds the Guinness Book of World Records for its 96-kilometers steepest rise in the altitude with a crossover of 800 bridges and viaducts.
Q1: What is Rail Gauge?
A rail gauge refers to the distance between the inner sides of the two parallel rails that make up a railway track. This measurement is critical as it determines the type of trains that can run on a track and affects stability, speed, and the type of terrain on which the rail can be laid.
Last updated on January, 2026
→ Check out the latest UPSC Syllabus 2026 here.
→ Join Vajiram & Ravi’s Interview Guidance Programme for expert help to crack your final UPSC stage.
→ UPSC Mains Result 2025 is now out.
→ UPSC Notification 2026 is scheduled to be released on January 14, 2026.
→ UPSC Calendar 2026 has been released.
→ UPSC Prelims 2026 will be conducted on 24th May, 2026 & UPSC Mains 2026 will be conducted on 21st August 2026.
→ The UPSC Selection Process is of 3 stages-Prelims, Mains and Interview.
→ Prepare effectively with Vajiram & Ravi’s UPSC Prelims Test Series 2026 featuring full-length mock tests, detailed solutions, and performance analysis.
→ Enroll in Vajiram & Ravi’s UPSC Mains Test Series 2026 for structured answer writing practice, expert evaluation, and exam-oriented feedback.
→ Join Vajiram & Ravi’s Best UPSC Mentorship Program for personalized guidance, strategy planning, and one-to-one support from experienced mentors.
→ UPSC Result 2024 is released with latest UPSC Marksheet 2024. Check Now!
→ UPSC Toppers List 2024 is released now. Shakti Dubey is UPSC AIR 1 2024 Topper.
→ Also check Best UPSC Coaching in India



