RAILWAYS & METROS INDUSTRY
PreciseSync NTP and PTP time server family keeps signalling, SCADA, passenger information and CCTV systems aligned to UTC, so an event logged at the relay room tells the same story as the record in the operations control centre.
<15 ns
GNSS SIGNAL LOCK TIMING ACCURACY
<100 ns
PTP, IRIG-B AND PPS ACCURACY TO UTC
184-ch
MULTI-GNSS PARALLEL TRACKING: GPS, GLONASS, GALILEO, BEIDOU
THE HIDDEN CLOCK BEHIND THE TIMETABLE
A modern rail or metro corridor is not one system. It is dozens of subsystems running side by side. Signalling and interlocking, traction power SCADA, passenger information displays, CCTV, access control and automatic fare collection all generate time-stamped records, and each one assumes its own internal clock is accurate.
Without a single disciplined time reference, those clocks drift apart. An interlocking event recorder logs a track circuit failure at 09:14:22.341. The OCC train graph sees the same event arrive 400 milliseconds later. The relay room disturbance recorder lands somewhere in between. The investigation team spends the next shift debating which timestamp is correct instead of identifying the root cause.
SERTEL engineered the PreciseSync family to eliminate that ambiguity. A satellite-locked Stratum-1 reference, hardened for trackside and equipment-room environments, feeds every protocol the corridor already speaks, NTP, PTP, IRIG-B and 1PPS, from a single appliance. Mount the antenna, assign an IP address, and every connected system locks to UTC within minutes.
The problem
These are the failure patterns our field engineers encounter most often during time-synchronisation audits on signalling upgrade and new-corridor commissioning projects.
Interlocking logs that tell three different stories
After a signal failure, the relay interlocking record, the electronic IED log and the OCC train graph each report a different time for the same event. Investigators spend more time reconciling timestamps than diagnosing faults.
Platform clocks and PIS displays running seconds apart
Passenger information boards and analogue station clocks drift independently once they lose a common reference. Commuters notice the mismatch before any maintenance team does, and the complaint goes down as a service failure, not a timing fault.
OCC and SCADA records that cannot be cross-referenced
Traction power SCADA, ATS audit trails and train graph software timestamp independently. During a service disruption, reconstructing the true sequence of events across systems takes hours, not minutes.
Compliance records rejected because timestamps disagree
Regulatory reporting, SOE data submissions and incident investigations require precise, consistent event timestamps. When protection relay logs and control system records disagree by even a few hundred milliseconds, submissions are challenged and investigations stall.
The Sertel solution
The PreciseSync-SMC-300 family handles NTP and SNTP synchronisation for OCC IT networks, SCADA and passenger-facing systems. The PreciseSync-GMC-300 family delivers PTP IEEE 1588v2 grandmaster capability for CBTC backbones, digital interlocking and IEC 61850-9-3 process bus environments. Both families share the same 184-channel multi-GNSS receiver, OCXO reference and hardened 1U rack design, and both are available in standard, fully redundant R and compact DIN rail variants to match any installation topology.
184-channel multi-GNSS receiver
Parallel tracking across GPS, GLONASS, Galileo, BeiDou and NavIC-IRNSS with a surge-protected antenna line up to 100 m, suited for rooftop and mast mounting at stations or depots.
Stratum-1 NTP / SNTP (SMC-300 family)
PreciseSync-SMC-300 serves thousands of NTP and SNTP clients, synchronising OCC workstations, SCADA gateways, PIS controllers and IT infrastructure to a single disciplined UTC reference.
PTP IEEE 1588v2 grandmaster (GMC-300 family)
PreciseSync-GMC-300 supports C37.238 Power Profile, ITU-T G.8275.1 Telecom Profile and IEC 61850-9-3, making it a precision timing grandmaster for CBTC backbones and digital train control networks.
IRIG-B for legacy signalling equipment
Modulated AM and TTL IRIG-B outputs keep relay-based interlocking, axle counters, event recorders and older protection relays on the same time base as newer IP systems, with no need for panel replacement.
OCXO holdover for underground and tunnel sections
A high-stability, oven-controlled crystal oscillator maintains microsecond-level accuracy when GNSS reception is temporarily lost in tunnels, underground stations or shielded equipment rooms.
Full redundancy with the R variant
PreciseSync-SMC-300-R and GMC-300-R incorporate redundant GPS receivers, master clocks, comparator units and dual power supplies, delivering uninterrupted time distribution for mission-critical OCC and station environments.
Applications
Operations control centre (OCC)
Synchronises train graph software, ATS audit logs, CCTV servers and OCC display walls to one UTC reference, so every control room system and every field event share a single timeline.
Signalling and interlocking
Feeds IRIG-B to relay-based interlocking cabinets and PTP to electronic IEDs, axle counters and track circuits, keeping post-incident event sequencing unambiguous across the whole corridor.
Traction power SCADA
Aligns substation SCADA, OHE monitoring, breaker event logs and energy metering to one time base, enabling accurate fault location and faster post-trip analysis on the traction power network.
Passenger information systems (PIS)
Drives platform display boards, public address trigger timers, station and depot analogue clocks from a single time source, eliminating the second-by-second drift that passengers notice between adjacent displays.
CCTV and fare collection
Timestamps surveillance feeds, AFC gate transactions and access control entries so footage and event records align precisely across every station, making incident correlation a matter of seconds, not hours.
Depot and rolling stock management
Synchronises onboard event recorders, depot maintenance management systems and wayside data loggers so train-side logs and trackside infrastructure records tell exactly the same story.
Product family
Choose an NTP or PTP time server from the PreciseSync family to match your specific installation form factor and redundancy requirement.
Compact 1U rack NTP time server
30 ns GNSS accuracy, 184-channel multi-GNSS, OCXO holdover, NTP/SNTP Stratum-1, IRIG-B AM/TTL, fibre and Ethernet outputs. For OCC IT networks and station SCADA.
Redundant NTP server, Eurocard format
Full redundancy across GPS receiver, master clock, comparator and dual PSU. OCXO holdover. Designed for mission-critical rail environments where continuous availability is non-negotiable.
DIN rail NTP server
Compact DIN rail form factor for panel-mounted installations. 184-channel multi-GNSS receiver with a 24-channel antenna, IRIG-B AM, NTP/SNTP Ethernet. Ideal for signalling cabinets and relay rooms with limited rack space.
Compact 1U rack PTP grandmaster
15 ns GNSS accuracy, 184-channel multi-GNSS, PTP IEEE 1588v2 with C37.238, G.8275.1 and IEC 61850-9-3 profiles, PRP support, IRIG-B and 1PPS outputs. For CBTC and digital signalling backbones.
Redundant PTP grandmaster, Eurocard format
Redundant GPS receivers, master clocks, comparator and dual PSU in a hardened Eurocard chassis. Full PTP IEEE 1588v2 profile support. For critical traction power and digital signalling infrastructure.
DIN rail PTP grandmaster
DIN rail-mounted PTP grandmaster with IRIG-B AM output, 184-channel multi-GNSS receiver with a 24-channel antenna, IPv4/IPv6 Ethernet. For signal relay rooms, trackside enclosures and space-constrained substation panels.
From our field notes
During a signalling modernisation audit on a multi-station metro corridor, the relay interlocking cabinets, the electronic IED nodes and the OCC ATS server were all running on separate free-running NTP sources. After a single track circuit anomaly, three different timestamps appeared in the incident report, a spread of nearly 500 milliseconds between the oldest relay log and the OCC record. The root cause analysis took four days because the team could not agree on which system's clock was authoritative.
A PreciseSync-GMC-300 was installed as the PTP grandmaster on the signalling LAN. IRIG-B was distributed to the relay interlocking cabinets through fibre converters, and NTP was enabled on the existing OCC workstations without any configuration changes to the client systems. Within one hour, every device on the network was locked to UTC within a few microseconds.
The next track circuit anomaly produced one clean, time-ordered event sequence across the relay log, the IED event record and the OCC ATS audit trail. The investigation closed in a single shift. That is the practical value of disciplined time on a rail network: one timeline, one version of events, and decisions made on facts.
Relevant products
GPS / GNSS NTP TIME SERVER
A 1U 19 inch rack Stratum 1 server with 14 ns timing accuracy under GNSS lock and a front-panel LCD. It drives slave clocks and digital displays directly, alongside NTP, IRIG-B and DCF77 outputs.
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GPS / GNSS NTP Time Server
Duplicated GPS receivers, master clocks, comparator units and power supplies on Eurocard PCB construction. Built for substations and control systems that must keep time through a component failure.
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Stratum-1 GNSS Time Server
A panel-mounted Stratum 1 server for control cabinets without rack space. It sends IRIG-B (AM) and NTP over Ethernet to SCADA, IEDs and protection relays from a single DIN rail unit.
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Stratum-1 GNSS Time Server
A compact 19 inch rack PTP time server with OCXO holdover and 15 ns timing accuracy under GNSS lock. One unit feeds PTP Ethernet, IRIG-B, 1PPS and any number of slave clocks.
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Redundant Stratum 1 GNSS Time Server
Redundant GNSS receivers, master clocks, comparator and dual power supplies in a 2U or 3U Eurocard chassis. Built for substations and control rooms where time must never stop.
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Stratum-1 PTP Time Server, DIN Rail
A panel-mounted PTP time server that fits inside control cabinets without rack space. Delivers IRIG-B (AM) and PTP Ethernet from a multi-constellation GNSS receiver with OCXO holdover.
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Digital Display
A six-digit wall clock that pulls time straight from your NTP server over the existing Ethernet network. The everyday choice for offices, control rooms and production halls that already run a time server.
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Digital Display
Shows the current date in large LED digits, synchronised to the same NTP source as your clocks. Pair it with a time display at shift boards, gate houses and reception areas so logs and records never disagree.
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Digital Display
A compact three-character display that names the day of the week, driven by NTP. Useful on shop floors and in maintenance bays where weekly schedules and rotating shifts decide who works where.
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Digital Display
A 28-character, multi-row LED board that combines time and date with live plant values such as frequency, MW output or ambient temperature. Reads data over Ethernet, OPC or 4-20 mA and supports scrolling and flashing messages.
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Digital Display
Our largest standard time display, built for turbine halls, warehouses and assembly floors where staff read the clock from a distance. Accepts NTP, PTP, IRIG-B, RS-232, RS-485 or differential pulse input in a wall-mount housing.
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Digital Display
A small-character NTP clock sized for panel fronts, server racks and operator consoles. It brings the same synchronised time to close-range viewing points where a wall display would be oversized.
Know moreFAQ
Talk to a SERTEL field engineer about specifying the right PreciseSync variant for your rail or metro corridor. We ship across India and the Middle East, configure on site, and back every deployment with full lifecycle support.
