Luas trams on the Tallaght line are crossing the notorious Red Cow interchange in west Dublin in 70 seconds, it has emerged.
The speed of the trams through the interchange would appear to vindicate the stance taken by the Railway Procurement Agency (RPA), that Luas would not need priority signalling, nor would it add to traffic congestion at the busy junction.
It would also appear to suggest that concerns expressed by the Minister for Transport, Mr Brennan, that Luas might need to be placed "on stilts", were misplaced.
The Minister commissioned a consultancy report on the stilts option last year before deciding instead on a complete overhaul of the Red Cow interchange.
The RPA acknowledged yesterday that there was "widespread disbelief" when it proposed crossing the M50 at the Red Cow interchange.
But a spokesman said recent testing of trams had vindicated the agency's position.
Tallaght-bound trams observed by this reporter over a three-hour period last Tuesday crossing the interchange - from the median on the Naas Road to the other side of the M50 - were consistently achieving times of one minute and 10 seconds to one minute and 20 seconds.
Between 5 p.m. and 6.30 p.m. the trams were able to achieve this time across the junction, even as traffic on the M50 itself slowed to a crawl, and tailbacks in vehicular traffic stretched up the Naas Road and along the N7 towards Newlands Cross.
According to the Luas spokesman, the observed times concurred with those observed by the RPA itself.
The spokesman said the trams did not require priority signalling because they were able to travel to the head of the queue on dedicated track running along the median of the Naas Road.
They were able to exploit the fact that vehicular traffic must stop at a red light, thus allowing the trams to move across the traffic to their dedicated bridge.
After this Luas crosses an M50 off-ramp, again exploiting the fact that traffic here must stop at a red light anyway.
The arrangement indicates that, should vehicular traffic at the junction increase, congestion would increase for all traffic except Luas.
The redesign of the Red Cow interchange to provide free-flow traffic for most movements is expected to cost in the region of €200 million.
However, this alone is not sufficient to ease the congestion which occurs north of the Red Cow on the M50, when northbound traffic merging from the N7 frequently slows to a crawl between this point and the toll bridge.
This congestion is unlikely to be alleviated until a third lane is provided on the M50.
Connex has said it still has not established the cause of a tram derailment on St Stephen's Green last weekend. A spokeswoman said she had "no idea" when the investigation might reveal a cause.
