One result of the upgrade not going ahead has been a “dreadful” three months for passengers according to Paul Stocks of the Shrewsbury-Chester rail users association. But performance has been poor for seven months.

Railtrack failed to estimate correctly the cost of the work, turning what had been envisaged as a low-cost exercise into one that had major engineering and cost implications, the Rail Passengers Council was told in December.

The timetable changes were made on 13 January after Wales & Borders replaced Central Trains as the operator on the Aberystwyth-Chester-Birmingham route in October.

The failure to implement the 90mph scheme meant that every train chalked up a 2.5 minute delay, made worse by congestion between Wolverhampton and Birmingham New Street, long sections of single-track and temporary speed restrictions.

The new timetable also involves the withdrawal of several trains although Wales & West says it will restore them “when we can do so”.

The operator also plans to have spare drivers and “where possible” a spare train.

It also plans to upgrade its train depot at Machynlleth, modify train couplings and issue more staff with mobile phones to try to improve performance.

Once we have achieved an improvement in train performance we will concentrate efforts on other areas, such as train cleanliness, passenger information at stations, seat reservation reliability, train catering and station facilities, said Chris Gibb, managing director of Wales & Borders Trains.