Non-Interlocked Working Procedures

Non-Interlocked (NI) Working

• NI working should be undertaken only as a last resort when a new gear installation can't be accomplished without it.
• DCM must calculate the anticipated losses from passenger and freight traffic to determine the monetary impact of NI working.
• Losses due to cancellation, short termination, diversion, rescheduling, detention to trains, and limitations on freight traffic bookings should be included.
• The traffic cost of NI working should be communicated to S&T to evaluate if new gears can be installed in a new building for a cost lower than the expected cost of NI working.
• If the cost of installing new gears in a new building is lower, the project should be carried out without NI.
• The entire exercise must be overseen by the DRM to ensure that all estimates are reasonable and no figures are unrealistic.
• NI working should be recorded on the original tracing, signed by the branch officers involved and the DRM.
• Major Works include overhauling of cabins, replacement of panels by panels at road side stations, meggering of cables, and changes in yard layouts.
• Minor Works include replacements of mechanical lever frames, panels, and RRIs.
• NI working is not recommended for any replacement operation except replacing a panel with a panel at a road side station.
• Existing facilities at a station undergoing NI working should be maintained and any changes to these facilities should be communicated in detail.
• NI working should be implemented for no more than 14 days, with a minimum of 3 days for smaller works and a maximum of 7 days for larger projects.
• Only one station within a division should undergo NI working at any given time.
• NI working should be planned during temperate weather to minimize the risk of wrong actions due to extreme weather conditions.

Planning for NI Working

• The Signal Plan for NI working should be finalized in HQ at least 45 days prior to the commencement of work.
• All plans and clearances, including CRS sanctions required for NI working, should be available one month before the start of NI working.
• The Signal Plan must indicate permissible routings and simultaneous movement facilities.
• The Signal Plan should clarify whether existing train movement facilities are to be curtailed, modified, or restricted.
• During NI working, changing points manually after a train passes takes around 10 minutes, impacting station capacity.
• Train movements should be documented with the exact sequence of points, whether in normal or reverse operation.
• Conflicting train movements should be identified and addressed by canceling, rescheduling, or diverting less important movements.
• Crossings and precedence should be minimized to ensure efficient train movement.
• Only 80% of the reduced capacity should be utilized during NI working to account for unforeseen failures like ACP or equipment malfunctions.
• Adequate cushions should be incorporated into train operations, with an initial focus on canceling, rescheduling, or diverting more trains than anticipated.

Staff Arrangements

• Each goomty should have one ASM and two Pointsman in each shift, with the ASM posted with the indoor ASM being called the coordinating ASM.
• Goomty ASMs are responsible for the working of points/levers under their charge and work under the direct supervision of the coordinating ASM on duty.
• Each zone should have one TI in charge of four or more goomties, who will periodically check and monitor the goomties under their charge.
• For major terminal stations, staff from adjoining divisions can be brought in to provide additional staff during NI working.
• NI working should not be started until all necessary staff are present and have received sufficient training.
• Staff with experience in NI working and those currently posted at major junctions should be prioritized.
• Comfortable boarding and lodging should be provided for outstation staff.
• Boarding and lodging can be catered to by using coaches at sidings or by setting up temporary dormitories.
• During the day shift, junior inexperienced staff from outstation should be deployed.
• Each goomty team should have at least one staff member with NI working experience.

Temporary Working Instructions (TWI)

• TWI is a set of instructions that replace the SWR of the station during NI working.
• While not as detailed as the original SWR, TWI must cover all aspects of train operation included in the original SWR.
• The static information of SWR remains valid, including inter-station distances, descriptions of yard layout, and level crossing gates.
• TWI replaces aspects of the SWR related to ensuring clearance of running lines, granting line clear, reception/despatch of trains, working of level crossing gates, and checks done by means of slots, lock bars, point locks, and signals.
• TWI should list the number of goomties, the portions of the yard each goomty controls, and the goomties involved for train receptions and departures.
• TWI should detail the procedures for obtaining line clear, ensuring track clearance, closing level crossing gates, setting routes, and identifying the involved points.

Non-Interlocked Working

• Non-interlocked (NI) working refers temporarily disconnecting signaling equipment such as points, signals, track circuits, axle counters for maintenance or modifications.
• NI working is typically necessary for tasks like overhauling levers, Yard remodeling, introducing new panel systems, or cable installation.
• It is a less safe system than interlocked working because safety measures are absent.
• During NI, it is critical for staff to be highly attentive as it increases safety risks.
• NI working inevitably slows train operations.

Avoiding NI Working

• It is preferable to avoid NI working altogether, especially when introducing new signaling equipment.
• Work on existing signaling equipment often requires NI working.
• New signaling equipment can typically be installed under traffic blocks, eliminating the need for NI working.
• The S&T department must clearly define the need for NI working within project proposals and specify the duration of NI working if required. This information should be noted on project drawings.

Planning for NI Working

• The Sr.DOM and Sr.IT (Senior Divisional Operations Manager; Senior Inspector Telecommunications) must provide details about:
  • Existing yard layout and its functionalities.
  • Works to be completed by various departments before, during, and after NI working.
  • Updated yard layout upon completion of NI working.
• Signaling plans should outline permissible train routes and simultaneous movement facilities.
• The signaling plan should clearly identify any curtailments, modifications, or restrictions to existing train movement facilities.

Timetabling Impact of NI Working

• Manually changing points after a train passes (under NI) takes approximately 10 minutes.
• The maximum capacity of the station needs to be calculated taking into account the time constraints associated with manual point changing during NI working.
• All train reception and dispatch movements must be documented along with:
  • Time of movement
  • Exact sequence of points (normal or reverse)
• Train movements sharing the same point should be assessed for conflicting moves; this is especially critical for movements scheduled within 10 minutes of one another.
• Conflicts involving point changes should be addressed by canceling, rescheduling, or diverting the less important moves.
• Crossing and train precedence should be limited as much as possible to facilitate smoother traffic flow.
• Only 80% of the reduced station capacity should be utilized to account for potential unforeseen delays caused by equipment failures or similar occurrences.
• It is recommended to initially cancel or reschedule more trains than anticipated to accommodate possible delays.
• Station facilities should be arranged to minimize staff walking distances to set points.
• The location of points should be clearly visible from the goomty (cabin).
• Goomties (small cabins) should be located near the first and last stop signals for efficient train management.

Staff Arrangements

• Each goomty should be staffed with:
  • One ASM (Assistant Station Master)
  • Two pointsmen per shift.
• Goomty ASMs are responsible for all points and levers under their care and work under the direct supervision of the coordinating ASM on duty.
• Multiple goomties should be organized into zones, each overseen by a TI (Traffic Inspector). The TI should regularly monitor the goomties within their zone.
• Major terminal stations may require additional staff from neighboring divisions.
• NI working should not begin without a full complement of trained staff.
  • Staff should have adequate knowledge of NI working and prior experience with NI procedures.
• Outstation staff should be provided with appropriate boarding and lodging during NI.
• Staff should be trained in detail regarding all aspects of NI working and post-NI changes.

Dissemination of Information

• Information regarding NI working and post-NI changes should be disseminated to all loco pilots, guards, and other running staff:
  • Yard plans should be displayed and staff should be instructed on the changes.
  • All running staff should acknowledge receipt of the information.
• Adjoining divisions and railways, as well as notice stations and interchange points, should also be notified of the NI working program.
• All control staff, including CHC (Chief Control Office), Dy.CHC (Deputy Chief Control Office), section controllers, power controllers, etc., should be thoroughly briefed on the changes.
• The public should be informed about potential train disruptions through newspaper advertisements, electronic media, and station announcements.

Telecommunications, Lighting and Medical

• Reliable communication is essential throughout NI working:
  • Communication must be established between the station and two adjoining stations on either side.
  • Satisfactory communication links should be in place between the station, cabins, goomties, and level crossing gates.
  • Backup communication links should be available between the control office and the NI station.
• Public address systems should be operational for announcements and warnings.
• Loudspeakers should be provided on each goomty for train movement announcements.
• Walkie-talkie sets should be provided to all supervisors working at site.
• Gangmen, keymen, and patrolmen within the 2 block sections on either side of the NI station should be equipped with walkie-talkie sets and electronic hand signal lamps.
• Adequate lighting should be provided at:
  • Level crossing gates.
  • Outermost goomties.

Introduction of NI Working

• The DRM (Divisional Railway Manager) or ADRM (Assistant DRM) must ensure that adequate arrangements regarding staff, safety equipment, lighting, telecommunications, and ground position are in place before allowing NI working.
• Prior to the start of NI working, operating/safety, engineering, signal, electrical, and mechanical branch officers should visit the working site alongside the DRM/ADRM. They should verify the availability of required arrangements before authorizing non-interlocking.
• On the day of NI working commencement, the Signal Inspector responsible for the NI work should issue a disconnection memo for the gears proposed for NI work.

Train Operation During NI Period

• A speed restriction of 15 kmph should be enforced over all points and crossings.
• A speed restriction board (15 kmph) must be displayed at the foot of the first stop signal.
• Caution aspects must be applied to the following signals:
  • Color light signals: Common NI home signal without route indicator.
  • MAUQ/TALQ (Magnetically Operated/Track Circuit Controlled Absolute Permissive): Single arm NI home signal.
  • Warning signals are deactivated by placing two cross bars.
• The NI home or starter signal can only be taken off after ensuring that:
  • All points on the route are correctly set, facing and trailing points are clamped and padlocked.
  • Facing points are correctly set, clamped, padlocked, and manned.
  • Level crossing gates are closed.
• The last stop signal should remain disconnected throughout NI working until the end of NI working.
• Train movements into and out of block sections should be controlled by the last stop signal.
• Paper line clears should not typically be issued to loco pilots for movement in the block section.
• A traffic block of 2-3 hours should be used for disconnecting the last stop signal and block instrument and reconnecting the new last stop signal with the new block instrument.

Train Running

• Each train movement must be announced on the loudspeaker well in advance, specifying the goomty involved.
• All points and crossings should be manually changed after each train passes, observing procedures for safety and accuracy.
• Loco pilots and guards must be fully aware of changes to track layout and signal indications during NI working.
• Staff should be equipped with lanterns, hand signals, and other appropriate tools for safe train movement and signal control.
• All procedures related to NI working should be followed strictly.