Baroness Williams said her party agreed with the East West link
Multi-million pound plans for a new rail line linking the East of England with the rest of the country have been given the backing in principle of the three main political parties.
The proposals, which could see Norwich, Ipswich and/or Stansted Airport linked to Bedford or Luton, have been proposed by the East West Rail Consortium.
Once in Bedfordshire, trains would go through to stations such as Oxford, Reading and Swindon under the plans.
The link has been backed by the East of England Regional Assembly.
The Labour government's Transport Secretary Lord Adonis, on a visit to Norwich, told the BBC: "The East-West rail link is an important project.
'Investment in services'
"We want to see big improvements in East-West rail services, for instance the Norwich to Cambridge started under this government.
"We want more East-West services but you're only going to achieve that if you have a party committed to investment in public services.
"We want to see a balanced approach to investment. Where we have got links, we want to see these links improved."
Founder member of the Liberal Democrats Baroness Shirley Williams, visiting Norwich, said: "In principle with the East-West link we are completely there.
"Big investment is still desperately needed. We don't favour another runway at Heathrow.
'Improve rail services'
"That's partly because we think that is where the money shouldn't go as distinct from where it should go which is into major rail investment."
But Baroness Williams said money would be tight and the "question is how soon you can invest in these rail projects".
A Conservative spokesman said: "I know how important improved rail services are for local people.
"Our plans to reform the railway, announced in February 2009, we focused on putting passengers at the heart of the railway.
"We will grant longer franchises to incentivise operators to invest more in the improvements passengers want to see happen.
"We will get a grip on Network Rail so schemes like the East-West Rail link deliver the best possible value for money for taxpayers and fare payers alike."