1. Indian Railways are committed to provide safe and efficient transportation system. In this context, Railway Signalling sub-systems promote safety, enhance line capacity and improve flexibility of the operations of the Railways. For meeting this commitment and to provide the designed safety, the need for adoption all over the Indian Railways of the standard practices and instructions for installation and maintenance of signalling sub-systems of types is thus of vital importance.

2. Considerable experience has been gained in the installation, operation and maintenance of signalling assets. Technological upgradation has also been continuously taking place. Since 1955 and particularly from 80s the strategy and practices of installation of Signalling sub-systems of types have gone through fundamental change from departmental execution to departmental supervision and execution by contracted agencies. In respect of maintenance philosophy, the thrust for intensive and predictive maintenance and optional/efficient use of the integrated blocks has been given. These developments have been reflected while preparing SEM Part-ll. The policy and special instruction issued during these decades have been appropriately incorporated in SEM-Part II comprising of 12 chapters.

3. SEM-Part II is the result of the efforts put in by a number of S&T engineers of the Indian Railways. I hope this will serve as a useful guide and compendium of instructions to all the officers and staff of the Signalling & Telecommunication Deptt. and will help them to develop better know-how of the prevalent system in respect of installation, maintenance and operation and thereby improve the reliability of the Signalling system.

New Delhi                                                                                          (N.K. Chidambaram)
September, 2001                                                                                Member (Electrical)
                                                                                                         Railway Board



First Edition of Indian Railway Signal Engineering Manual (IRSEM) was issued in January, 1955. IRSEM had 22 chapters covering the requirements of signalling, requirements and instructions for installation & maintenance of Signalling Systems/Equipment and Organisation Structure of Signalling & Telecommunication Department.

With the technological upgradation and developments, the review of Jan.'55 Manual became necessary which was undertaken by Sh. CM. Joseph, CSTE (Retired) in 1980 and later by a committee headed by Sh. S. Narasimhan, OSD/Signal Engineering manual (CSTE/Southern Railway). It was then decided to publish SEM in two parts. SEM-Part I containing 10 chapters and covering requirements of Signalling, organisation structure of S&T and matters connected with Budgeting, Planning etc. had been issued in Jan. 1988.

The work on Signal Engineering Manual (SEM) Part II was subsequently undertaken. SEM-Part II caters to the requirements and instructions of installation, operation and maintenance of the Signalling subsystems and equipments of types. The technological development in the form of Block Proving by Axle-Counter, Integrated Power Supply Arrangement for Signalling, Axle Counters, Relay and Electronic Interlocking besides the special practices and instructions for the installation of the Signalling System in 25 KV AC traction area have been appropriately covered. Specific chapter has also been made for Level Crossings. The Manual also incorporates the various technical policies, letters/circulars issued by the Board during this time to meet the changing needs of Reliability, Availability, Maintainability & Safety (RAMS) of the Signalling Sub-system. In respect of subjects like Traffic Management System (TMS), Automatic Trains Protection (ATP), ATO & ATC and OFC based Signalling which are likely to be brought into use on the Indian Railways in the near future, the instructions would be drawn based on the experience of the adoption of these technologies and if necessary, associating consultants/experts on the subject.

The evolution of each of the 12 chapters of SEM Part II passed through the stages of drafting and examination by Expert Committees involving RDSO and the Railways. Their detailed deliberations and discussions by the Signal Standards Committees were thoroughly scrutinised at the Board's level.

In as much as the common measure of agreement amongst the Railways in regard to the maintenance schedules, their periodicity, the format and registers of recording of checks, tests, measurements and the operating conditions obtaining on the Railways, the basis have been standardised, subject, of course to the conditions that the Chief Signal and Telecom Engineer of the Railway may, where considered essential, authorise deviations to the prescribed practices and the procedures to the extent necessary.

It will be appreciated, that in a manual of this nature, it may not be feasible to include material to cover each and every contingency that may arise in the course of installation, working and maintenance of signalling installations, though efforts have not been spared to make it as comprehensive as possible. In the event of any contingency that might arise requiring supplementing what is contained in this Manual so as to suit the conditions on a particular Railway, the Chief Signal & Telecom Engineer of the Railway may issue necessary instructions for the purpose. Copy of such instructions may be docketed to Railways, RDSO as well for their benefit and record. However, the provisions in this Manual, the Codes/ Manuals issued by various authorities, the General and Subsidiary rules and any other statutory regulation in force shall not be contravened.

The finalisation of SEM-Part II has been a stupendous task. It has been addressed through the efforts put in by a number of Senior Officers as well as staff of the Railways, RDSO and Railway Board. No amount of words of appreciation and gratitude to them will be adequate for the purpose.

It is sincerely hoped that the Manual would serve the needs for which it has been made.

New Delhi                                                                                        (M. L. Gambhir)
September, 2001                                                                              Adviser (Signal)
                                                                                                      Railway Board