Page 282 - IRSEM_Main Book

Chapter 12: Installation, Testing & Maintenance of Mechanical
Signalling Equipment

Section 1: Installation

12.1.1 Lever Frame

Conformity to Drawings and Specifications: Interlocking frames shall
conform to approved drawings and specifications.

12.1.2 Marking of Parts

(a) Standards, quadrants, quadrant supports, levers shoes, locking boxes
and covers, shafts and intermediate supports shall be marked with
identifying letters or figures painted on them.

(b) Plungers, interlocking bars, mechanical interlocking locks and other parts
constituting the 'Locking’ shall be stamped as under:

(i) Plungers shall be marked with their relevant lever numbers and
number of the ‘locking' box;

(ii) Interlocking bars shall bear the number beginning from the first left
hand side lock to last right hand side lock, the number of the channel
of the locking box, and its position in the channel; and

(iii) Mechanical interlocking locks (popularly called 'dogs') shall be marked
with their respective lever number and the number of the channel of
the locking box.

12.1.3 Assembling Mechanical Locking: Mechanical locking shall be assembled
in accordance with approved Locking Diagram. Approval shall be obtained
for any alteration, constructional or technical, found essential during the
course of assembling locking. Some important instructions for assembling
locking are detailed below:

(a) Locking boxes shall be correctly aligned.

(b) All pin joints shall be made a proper fit with no slackness. This is of
particular importance in catch handle type of locking where a number of
pin joints are provided to work the locking through the catch handle. For
newly fitted locking frames there shall be practically no lost motion in
connections or locking. Levers shall be straightened where required to
maintain proper alignment. It shall be ensured that all parts of the lever
frames including spare levers and their tappets are intact.

(c) Notches shall be marked off in accordance with the locking diagrams.
Marking shall be done with the help of templates and the outline punch
marked.

(i) In the case of catch handle locking, it is most important that the catch
rod and links are in correct position before marking.

Chapter 12: Installation, Testing & Maintenance of Mechanical Signalling Equipment Page 236 of 535