THE SIGNAL BOX

OVERSEAS

INDIAN RAILWAYS SINGLE LINE INSTRUMENTS

Edited by Apurva Bahadur

DESCRIPTION OF TOKEN BLOCK INSTRUMENT

Note:- the term 'Station Master' wherever used in this Manual, also applies to Assistant Station Masters, Cabin Assistant Station Masters, Switchmen and any other competent staff who may, for the time being, be incharge of Block Working.

Token Block Instruments.

(1) The types of Token Block Instruments in use on the Single Line sections of the Indian Railways are -

  1. Neale's Ball Token Instrument.
  2. Neale's Voucher Block Instrument.
  3. Neale's Tablet Token Instrument
  4. Theobald's key Token Instrument.
  5. Webb & Thompson Electric Train Staff Instrument.

Other interlocking:-

  1. Indoor apparatus
  2. Outdoor apparatus

Description of Neale's Ball Token Instrument

Neale's Ball Token Instrument
(A) The token receiver cover The token receiver cover should be lifted for inserting the token into the instrument
(B) Token Receiver handle. This should be turned token to fall into the instrument.
(C) Galvanometer. This indicates the flow of current from one instrument to another
(D) Telephone This is provided in conjunction with the instrument for communication with the station at the other end of the block section.
(E) Plunger This is used for transmission of Bell Code signals and operation of Operating Handle.
(F) Operating Handle. .This can be set at "Line Closed" or "Train Going To" or "Train Coming From" positions. It can be turned to any one of these positions, when a prolonged beat is received from the station at the other end of the block section.
(G) Token Exit. A Token comes out through this exit when the Operating Handle is turned to the "Train Going To" position.
(H) Token Windows. This indicates the availability of tokens in the instrument.
(I) Token Indicator. The indicator shows a green disc if there is a token and a red disc if there if no token in the instrument.
(J) Bell. This responds to Bell Code signals given by the station at the other end of the block section. At stations provided with more than one instrument different bells or gongs with distinctive sounds are fitted up to identify the individual instrument.
(K) 'E' type lock with key in 'Train Going To' position This is provided where the Last Stop signal is controlled mechanically through the Block Instruments. The key can be released only when the block handle is in "Train Going To" position and is used for controlling the Last Stop signal lever. This key can also be used for controlling the slip siding points
(L) ' E ' type lock with key in 'Train Coming From' Position. This can be released only when the Operating Handle is in the "Train Coming From" position and is used for controlling the catch siding point
(M) Station Master's key. When the key is taken out, it locks the instrument in the last operated position and, only incoming beats can be heard. This key should be kept in the personal custody of the Station Master when it is not required for operating the instrument.

Note:- The number of the token and the code initials of the two stations at each end of the block section to which the token applies are engraved on each token. Tokens are provided with grooves of a different pattern for different sections. Ball tokens are provided in 4 different classes viz. A class, B class, C class and D class for different block sections.

Instruments of this type were latterly manufactured by Westinghouse in the UK and although they were never used in the UK they were exported to a number of countries.

Description of Neale's Voucher Block Instrument

Neale's Voiucher Block Instrument
(A) Aperture for inserting tokens Through the aperture slot a ball token is put into the Block instrument.
(B) Galvanometer This detects the flow of current from one instrument to another.
(C) Telephone This is provided in conjunction with the instrument for communication with the station at the other end of the block section.
(D) Bell plunger. This is used for the transmission of Bell Code signals and operation of Operating Handle.
(E) Operating Handle. This has three positions, "Line Closed' ',"Train Going To", and "Train Coming From". It can · be turned to any one of these positions when a prolonged beat is received from the station at the other end of the block section. Note: When a token is dropped in, the Operating Handle can be brought to "Line Closed" position without the cooperation of the Station Master at the other end of the block section.
(F) Token Delivery cup A token comes out through the token delivery cup
(G) Bell This corresponds to the Bell Code signals given by the station at the other end of the block section. At stations provided with, more than one instrument different 'bells or gongs with distinctive sounds are fitted up to identify the' individual instrument.
(H) Station Master's key When the key is taken out, it locks the instrument in, the last operated position. This key should be kept in the personal custody of the Station Master when it is not required for operating the instrument.
(I) Switches for controlling locks. The left-hand switch controls the token lock and shall be pressed while extracting the token. The right-hand switch shall be used when turning the handle to"Train Coming From" or clearing back or canceling.
(J) 'E' type lock with key in 'Train Going To' position. This is provided where the Last Stop signal is controlled mechanically through the Block Instruments. The key can be released only when the block handle is in "Train Going To" position and is used for controlling the Last Stop signal lever. This key can also be used for controlling the slip siding points.
(K) 'E' type lock with key in 'Train Coming From' position. This can be released only when the Operating Handle is in the "Train Coming From" position and is used for controlling the catch siding points.

Note: The number of the token and the code initials of the two stations at each end of the block section to which the token applies are engraved on each token. Tokens are provided with grooves of 3 different patterns for different sections viz. broad groove, narrow groove and double narrow groove.

Description of Neale's Tablet Token instrument

Neale's Tablet Token instrument

The instrument is similar to Neale's Ball Token instrument except for the following differences:

  1. Token slide with Handle :- A token slide is provided at the top of the instrument instead of a Token Receiver cover. A tablet token is inserted into the instrument by pulling out the slide, placing the tablet token in the recess and pushing back the slide.
  2. The Neale's Tablet Token Instruments are provided with Tablet windows instead of token indicators.

Description of Theobald's key instrument

An example of this type of instrument can be seen on the Madras Beach page

(A) Key Token. It consists of a metal key with lugs at both ends and a tongue at the center; the lugs suit the key guards of the instrument. Each token is engraved with the number of the token.
(B) Key guards The Key Guards are small metal brackets provided on the face of the instrument on either side to receive a token of a definite class.
(C) Galvanometer. This detects the flow of current from one instrument to another
(D) Plunger This is used, for giving Bell Code signals and permitting extraction of a token.
(E) Bell. This responds to the Bell Code signals given by the station at the other end of the block section. At stations provided with more than one instrument different bells or gongs with distinctive sounds are fitted up to identify the individual instrument.
(F) Locking bolt and padlock The locking bolt should be fitted in the slot for preventing token being taken out, It should be padlocked when it is not in use and the key is kept in the personal custody of the Station Master to. prevent unauthorised manipulation of the instrument.
(G) Token Magazine Key tokens are stored in the staff magazine.

Description of Webb & Thompson Instruments

Webb & Thompson Instrument
(A) Indicator Needle/Dial indicating "Staff In" and "Staff Out" In case of 'M' type instrument the indicator needle indicates "Staff in'" and "Staff Out " and in the case of 'S' type instrument the dial indicator indicates "Staff in" and "Staff out".
(B) Galvanometer Needle The Galvanometer Needle indicates whether the station at the other end of the block section is authorising extraction of 'Staff' or that the 'Staff' has been extracted.
(C) Cut out switch knob This should be pressed after extraction of the 'Staff' from the station at the other end of the block section that the 'Staff' has been extracted
(D) Brass Thumb Plate
(E) Staff inlet and outlet Through this, the 'Staffs' are inserted into or withdrawn from the instrument.
(F) Staff Magazine The 'Staffs' are stored in the Staff Magazine
(G) Train staff The Train Staff token is an iron bar about 300 mm long with a brass cap at one end about 50 mm in length on which are inscribed the number of the staff and also code initials of the stations at each end of the block section to which it applies. The Train Staff is provided with rings of different patterns for different sections.
(H) Generator The handle of the Generator should be rotated in clock wise direction generating the current for transmission of bell beats and extraction if the Staff token at the other end by pressing the Key plunger pertaining to the block section
(I) Key plungers They are provided for signaling Bell Codes to the station on either side by depressing the appropriate Key plunger and the Generator handle being turned.
(J) Bell This responds to the 'Bell Code signals given by the station at the other end of the block section. At stations provided with more than one instrument different bells or gongs with distinctive sounds are fitted up to identify the individual instrument.
(K) Block Telephone This is provided in conjunction with the instrument for communication with the station at the other end of the block section

Indoor Apparatus.

The control on the last stop signal may be:-

(1) For Neale's Ball and Neale's Tablet and Voucher Block Instruments.
  1. By using 4 mechanical control key extracted from the instrument adjunct on receipt of Line Clear to release the Last Stop signal, or
  2. By electrical control on reverser being released when Operating Handle is turned to 'Train Going To' position, or
  3. By electrical lever lock on route lever for dispatch being released when Operating Handle is turned to 'Train Going To' position.
Note: There is no control on Last Stop signal through the Block Instrument where Webb & Thompson Instruments are provided.
(2) Theobald's key Token instrument. By means of Station Master's control slide which should be pulled before extracting a token.
Note
  1. Where Starters or Advanced Starters are not provided in the Upper Quadrant territory, the 'proceed' aspect of the Main Home signal should be controlled through the Block Instrument and in Lower Quadrant territory, the 'proceed' aspect of Main line Home signal should be controlled through the Block Instruments.
  2. Block Line will be cut if extraction of token is not done carefully. If this happens, the Station Master's control slide should be normalised and reversed again and extraction of token should be done thereafter.

Outdoor Apparatus

An electric signal reverser is provided in most of the cases for controlling the Last Stop signal.

Additional notes by Robin Wickenden