Latest News

Result of Train Manager (Goods Guard) Departmental Exam

What kinds of block instruments are or were used in India?

July 16, 2019, 12:37 PM
Share

In India, the most prevalent form of physical token system to be found in recent decades is the Neale’s Ball Token System and variants such as Neale’s Voucher Block, Neale’s Tablet Token, etc. Other systems such as Theobald Key Token, Webb and Thompson electric token staff, Tyer & Co.’s key token instrument (one-wire three-position instrument and others), etc., were also widely used.

Robert’s Key Staff instruments were used to control single lines on the Mysore State Rly. and the Madras and Southern Mahratta Rly. Neale’s Ball Token came into wide use in the interbellum years just before Independence. Mr Neale, by the way, was an engineer on the GIPR. Most early block instruments followed British designs and practices.

Neale’s token system was innovative when it was introduced, as it combined, for the first time, the token handling system with the block instrument operation into a single system.

Tokenless block instruments aim to do away with the time-consuming process of manually exchanging tokens. Tokenless operation on single lines is more recent, having started in the 1970s. Among tokenless systems used today by IR, common types of block instruments include push-button tokenless single-line block instruments made by the Signal & Telecom Workshops of SR at Podanur, Diado single-line tokenless instruments, Kyosan single-line tokenless instruments, etc.

Tokenless working of double line sections is much older, because of the inherent safety factor of not having to worry about opposing train movements on the same line. For double-line sections, tokenless instruments made by a collaboration between Siemens (Germany) and General Electric Co. (UK) were in wide use; these are still known as ‘SGE’ instruments although they are now manufactured at the Podanur workshops.

There are also the so-called Double Line Lock and Block instruments (see below for Lock and Block working) which rely on a mechanical route-blocking arrangement activated by the presence of a train, (the wheels depressing a treadle that activates the interlocking to ensure only one train is on a block section at a time — or indeed, even achieving interlocking between signals under the same cabin). Early on different kinds of Lock & Block instruments were in use on heavy-traffic lines in India; instruments were from Sykes & Co. and other manufacturers.

Source – IFRCA.org

Share

This entry was posted in 2 Railway Employee, STUDY NEW, Railway Employee