Railway line telecom and signalling standby power retrofit

Project background

A railway operator in Hebei province maintains a corridor of telecom and signalling equipment rooms. Each room is modest — a rack or two of transmission equipment, a signalling interface, some lighting — but there are many of them, and they are spread along the line rather than concentrated at a station.

The legacy arrangement used lead-acid battery strings at every site, maintained by scheduled vehicle patrols. Three problems compounded:

• Patrol cost. Dispatching a vehicle to a single small site often cost more than the equipment being inspected.
• Late detection. Lead-acid capacity fades silently. There is no visual indication, so a degraded string was usually discovered during an actual outage.
• Short service life. Grid quality at some trackside locations is poor, and float life was compressed to one or two years.

Design approach

Battery replacement

Existing lead-acid strings were replaced with 48 V 50 Ah rack-format LiFePO4 packs. Because the modules follow standard 19-inch dimensions and terminal layout, the change needed no modification to the existing cabinet structure or DC cabling, which allowed the work to be staged site by site without interrupting traffic operations.

AC load support

Some sites carry 220 V AC loads — monitoring hosts, work lighting, small test equipment — that could not be fed from the 48 V DC bus. A rack inverter taking its input from the same 48 V bus was added at those sites, so AC and DC loads share one battery bank instead of requiring a second small UPS with its own batteries.

Remote monitoring

Each site was fitted with a communications card reporting to a central platform. The platform shows, per site:

• mains status — present or failed
• battery health and remaining capacity
• load percentage and cabinet temperature
• alarm events pushed as they occur

Results

The measurable change was not the battery chemistry; it was the visibility. Battery condition moved from "known only after a site visit" to "visible on a dashboard", and maintenance switched from fixed-interval patrolling to alarm-driven dispatch. Vehicle trips fell noticeably within the first year.

Battery replacement interval extended from one to two years out to three years and beyond, and the operating cost difference became visible in the second year, once the capital cost of the first replacement cycle had been absorbed.

In distributed deployments of this kind, the monitoring layer often saves more than the battery itself — which is why a communications card belongs in the base scope of a multi-site rollout rather than in the options list.

What transfers to other projects

• Standardise the DC interface, not the site. A 48 V rack format let one spare module cover every site, which matters more than any single specification number when you are supporting dozens of locations.
• Stage the rollout. Site-by-site replacement with no cabinet modification meant no scheduled downtime and no permit complications.
• Instrument first if the fleet is large. Without remote reporting, the economics of a lithium retrofit rest entirely on cycle life, which is a slower and less certain payback.
• Share the battery between AC and DC loads. A DC-fed inverter is usually cheaper than a second UPS, and it removes a second battery bank from the maintenance list.

Scope boundary

This arrangement suits trackside rooms, remote telecom sites, pipeline and highway cabinets, and any location where the load is a few kilowatts and the constraint is access rather than power. It is not a substitute for a substation-grade power system where dual supplies, transfer schemes and protection coordination are part of the design.

Product references: HC series 19-inch rack LiFePO4 battery, ET 1–10KRS rack UPS with external LiFePO4, cloud monitoring card, and battery cabinet configuration.