J Slab Track System

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• Japan to train 1,000 Indian engineers before transfer of bullet train technology.

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• Indian engineers will be trained by Japanese experts before starting work on the High-Speed Rail Track system for Mumbai Ahmedabad High Speed Rail corridor (MAHSR).
• The bullet train being built between Mumbai and Ahmedabad will use the ballastless Slab Track system (popularly known as J Slab track system) as used in Japanese Shinkansen high speed railways.

What is the J Slab Track System?

• A ballastless track or slab track is a type of railway track infrastructure in which the traditional elastic combination of ties/sleepers and ballast is replaced by a rigid construction of concrete.  
• Slab Track was invented and has evolved in Japan and now the term is synonymous with High Speed Track. 

How did it came into use? 

• The first HSR in Japan i.e. The Tokaido Shinkansen began operational in 1964 between Tokyo and Shin-Osaka. Conventional ballasted track structure was adopted in Tokaido Shinkansen. 
• Track geometry of conventional ballasted tracks used to disturb frequently with the increase in traffic density. Due to the problem of disturbance of track geometry coupled with reduction in time available for maintenance and labour shortage, the need was felt to introduce a low maintenance track. 

Significance

• Performance of Slab Track is better for High Speed Railway compared to ballasted track due to its higher flexural stiffness and it is because of this that the forces in Slab Track are distributed over a larger area and deflections are considerably less compared to ballasted track. This ultimately results in lesser maintenance requirements in Slab Track structure.
• Although initial construction cost of Slab Track is higher compared to ballasted track, the difference is compensated within a few years of operation because of less maintenance and labour requirements in Slab Track. 
• Slab Track structure is particularly advantageous in case of viaduct and tunnel due to its lighter and sleek structure.

Source: TH