A FATALITY OR serious injury could have occurred when a Luas tram collided with a faulty section of the overhead contact system, pulling down an electrical cable and damaging the underside of a railway bridge, an investigation has found.

The incident occurred on the approach to Beresford Place railway bridge in Dublin city last June after an electrical short broke part of the overhead mechanism, leaving a section hanging down over the tramline.

Around four hours later, a tram struck the damaged section and the contact wire became entangled in the vehicle’s pantograph, cutting power to the O’Connell to Spencer Dock section of the line.

It continued to move forward, pulling down the feeder cable, and the pantograph collided with the underside of the bridge, dislodging a number of insulation plates before coming to a stop 30 metres after the point of impact.

A report by the Railway Accident Investigation Unit (RAIU), which was published last week, stated that a fatality or serious injury could have been caused under slightly different circumstances as a result of heavy objects falling in a public area.

The investigation found that the initial electrical short had been caused by a break in one of the kevlar connectors in the overhead contact system, which were in the process of being replaced with stainless steel links at the time of the accident on 11 June 2021.

This caused a bright flash and power was cut to a section of the tramline. A maintenance crew was dispatched to the location at 1.25am and reset circuit breakers, but they did not conduct a visual survey of the section.

The incident caused an electrical flash on the Luas line Source: Abbey Street Platform CCTV via Railway Accident Investigation Unit

The RAIU said that such a survey would have identified a partially detached section of the overhead contact system, and said the absence of any requirement to conduct such an inspection was a systemic factor in the accident.

The driver of a ‘sweep tram’ that approached the Beresford Place railway bridge at 5.12am was therefore unaware of the hazard, and struck the cross-span assembly. There were no passengers on board at the time.

The incident occurred on the approach to Beresford Place railway bridge in June 2021 Source: Railway Accident Investigation Unit

The tram’s pantograph, which connects to the overhead powerline and conducts 750 volts, was “severely damaged” beyond economic repair, and 100 metres of the overhead contact system had to be replaced as a result of the accident.

Three insulated plates on the underside of the railway bridge had to be replaced, and there was a short delay to an Irish Rail passenger service from Dublin Connolly to Bray while the damage was inspected.

The investigation report made no safety recommendations due to a number of actions already taken by the Luas operator. These include the ongoing replacement of kevlar connections with stainless steel wires.

In addition, a full ground survey of an electrical section is now required in the event of an electrical short.