Lima Metro Line 2: Communications Architecture for OCC, Tunnel Radio, and CBTC Synchronization

Lima Metro Line 2: operational scale and complexity

Line 2 is Peru's largest public infrastructure project in decades: 35 km, 27 stations, mixed underground (tunnel under Av. Colonial and Carretera Central) and elevated operation, with full CBTC, platform screen doors, and a centralized OCC in Ate. The communications architecture — OCC dispatch, tunnel radio, CBTC timing, and maintenance connectivity — is as critical as the track or the rolling stock.

OCC multi-channel dispatch: Zetron ACOM

A metro OCC operator simultaneously manages 6+ radio groups: train drivers, station supervisors, trackway maintenance, fixed installation maintenance, multiagency emergency channel, and IP telephony. Managing these from separate consoles is operationally impossible during incidents. Zetron ACOM integrates all radio groups and telephone lines into a single touchscreen, supporting up to 8 simultaneous active channel patches. Emergency patch function links train driver, nearest station supervisor, and emergency services into a multi-group conference with a single action. Full TETRA/P25 integration via ISSI/CSSI gateway. All OCC communications recorded by Zetron ADAM with UTC millisecond timestamps and SHA-256 evidence packages — required by modern metro concession incident investigation standards.

Tunnel radio: leaky feeder architecture

Conventional radio does not propagate beyond 200-300m in circular concrete tunnels. The international standard — used in metro systems in Madrid, Paris, São Paulo, and Medellín — is leaky feeder (radiating cable): a coaxial cable with slotted outer conductor running the full tunnel length as a distributed antenna. Line amplifiers every 400-600m maintain uniform signal level. DAS antennas in station platforms and mezzanines extend coverage to passenger areas and also support public cellular operators. The tunnel radio concentrator integrates with the OCC Zetron system via standard ISSI, making tunnel TETRA groups accessible from the ACOM console identically to surface radio groups.

CBTC time synchronization: why 1 microsecond matters

CBTC safety depends on time synchronization between all system elements: onboard ATP/ATO, track balises, Zone Controllers, and the OCC supervision server. Major CBTC manufacturers (Alstom, Siemens Mobility, Thales) specify 1-10 microsecond synchronization precision — unachievable with conventional NTP (1-10 ms typical accuracy). Bitstream TS-3000 acts as PTP Grandmaster IEEE 1588 v2, distributing < 100 ns time to all CBTC nodes via Bitstream Transparent Clock-capable switches. Dual TS-3000 in active-passive configuration with BMCA automatic failover < 1 second.

Rajant Kinetic Mesh for depot and maintenance

The Line 2 depot in Ate requires communications for maintenance teams across a large workshop with heavy metal equipment, mobile maintenance vehicles, and night-window track brigades. Rajant BreadCrumb ME4 nodes on maintenance HiRail vehicles and cranes act as moving mesh nodes, eliminating Wi-Fi dead zones. Night track brigades carry portable nodes that extend the mesh dynamically into the tunnel, providing CMMS work orders and inspection video to the depot supervisor in real time.

EMAR SYSTEMS supplies the communications components of this architecture as authorized Peruvian distributor: Zetron (ACOM consoles and ADAM recording), Bitstream (TS-3000 time servers and PTP switches), and Rajant (BreadCrumb nodes for depot and maintenance brigades), with architecture design, CBTC manufacturer integration, and local technical support under documented SLA for critical transit infrastructure.