Philip Purdy, TfGM's Metrolink Director, said: 'Unfortunately, we had tram failures at key locations on the network on two consecutive evenings - Tuesday and Wednesday - and both during the very busy peak period.
'We fully appreciate that any disruption to services can be annoying, but that it's felt particularly keenly at the busiest times, when people are making their way home from a hard day at work, so I'd like to apologise to anyone who was affected.
'While we know that it simply wasn't an acceptable level of service, we endeavoured to keep all our customers informed and have people on the ground to provide support.
'In both cases, services were affected by faults with the older vehicles from the fleet - known as T68s. There are 32 in total and the vast majority of them have been in service since 1992, so they are nearly 20 years old.
'They are considerably less reliable than the new yellow-and-silver M5000s and we're fully aware of how that can affect the reliability of services. That is why we are investing in replacing 12 of these original - and oldest - trams with brand new M5000s.'
