LONDON (Reuters) – Commuters at Britain’s busiest rail station faced yet another day of disruption on Tuesday, marked by delays and cancellations rather than the planned return to full service after a month of improvement works.

A test to the upgrade at Waterloo, intended to increase the capacity of a station which handles some 100 million journeys a year, identified a fault with the signalling equipment, leading to yet more misery for commuters.

For most of August, they had been advised to take holiday, work from home or find an alternative route as the 800 million-pound ($1 billion) works were carried out.

In a statement, rail operator Network Rail apologised to passengers and said the continued interruption to services was due to “safety critical” work.

Delays were expected until midday.

Commuters took to Twitter to express their frustration, with many joking that despite the disruption, the station’s re-opening did mark a return to normality.

Greg Wetherall wrote: “Cancelled trains and delays. The ‘new’ Waterloo; much like the ‘old’ Waterloo then.”