The fifth of the narrow-gauge Kalka – Shimla Railway ZDM3 NG loco is ready to be shipped to the Northern Railway. The Central Railway Loco Workshop at Parel in Mumbai is the manufacturer of the loco. The loco is meant for hauling passenger and goods trains on the Kalka – Shimla Railway Section of Ambala Division of the Northern Railway. This loco is a part of an order for 12 ZDM3 NG diesel-hydraulic locomotives placed with the Central Railways Parel Workshop. The workshop has already manufactured and dispatched four of these locos since November 2019.
The Kalka – Shimla Railway is a 2 ft 6 inch (762 mm) gauge railway that runs from Kalka at the foothills of Himalayas to Shimla in the hills of Himachal Pradesh. It runs through the Sub-Himalayan region and rises to a height of 1400 meters in a route length of 97kms. This is a UNESCO World Heritage Railway. On November 2nd, a routine trial run of the 114-year-old heritage KC 520 steam locomotive engine was also conducted after the COVID-19 lockdown lifting.
The ZDM3 NG loco is equipped with a dual cab to drive from either end with good visibility of track ahead. The locos can cold start ensuring their working in severe winter conditions in Northern India. The ‘On-demand cooling system’ cools the engine as per requirement, especially during harsh summer times. The air brakes are similar to Broad Gauge Locos. The diesel engine performance parameters are exhibited on the electronic screen. The safety features include an Automatic Emergency Braking, a Vigilance Control Device and an Electronic Speedometer with a recorder. The heavy-duty compressors cater for future requirements of air brake trailing loads. Hand brakes are provided on both Driver’s Cab. This loco uses a hydro-Mechanical transmission also known as Suri transmission consisting of one converter and hydro-mechanical clutch system. The Suri hydro-mechanical type transmission features a Trilok converter coupling and synchronizing fluid coupling with plate clutch for higher efficiency.
For dieselization of the narrow gauge sections, the Indian Railways had decided to adopt a B-B design of 8.5 t axle load with a provision to modify the same to 1B’-B’1 design to reduce the axle load to 6t. The Kalka-Simla section was the first one to run a ZDM3 class loco. The design of power equipment is similar to that of WDS4 class locomotives. ZDM3 is equipped with a single Mak model 6M282A (K) turbocharged aftercooled diesel engine with Voith governor. The Voith turbo-reversible transmission has one converter for each direction of travel. The dynamic braking is achieved by emptying the filled converter and filling opposite direction converter. This model has no mechanical reversing system.
The Parel workshop is one of India’s oldest railway workshops. In addition to the manufacture of the ZDM3 locos, the workshop repairs and overhauls diesel locomotives, diesel cranes and rehabilitation of mainline coaches. It also manufactures many components for diesel locos, carriages and wagon.