Putting Paris Metro style rubber wheels on UK trains could allow a higher number of services to run along existing tracks , according to a report produced the Economic Competitiveness Policy Group chaired by MPs John Redwood and Simon Wolfson for the Conservative Party shadow cabinet (link below.)
http://www.railchat.co.uk/phpBB2/viewtopic.php?f=9&t=11858&start=0&st=0&sk=t&sd=a

Freeing Britain to Compete presents proposals for increasing the capacity of Britain's rail network within budget constraints. It says the current emphasis on improving signalling and lengthening trains is not nearly as effective at raising capacity as improving the traction on trains could be. The document claims that the rail industry allows a maximum of 24 trains an hour to run on a typical commuter track because the braking and accelerating time trains spend on station approaches makes it unsafe to run additional services.

However , the report says the Paris Metro has overcome this problem by introducing rubber wheels that give trains extra grip , enabling them to accelerate more smoothly and brake more quickly. The Montreal Metro system also uses rolling stock with rubber tyres producing the same advantages while some metro vehicles , the document claims , can also be driven on to roads.

The report's authors add that if introduced to British commuter trains , rubber wheels could allow train operators to run 40 services per hour over a stretch of track - an increase in capacity of about 65%. Rubber could be introduced either in the form of additional wheels on a special running strip , or on the steel wheels. While the report admits there would be costs to adapt the trains , it says these would be modest compared to the costs of alternative solutions to increasing capacity.

Interesting end quote :

"In a bid to cut bureaucracy and streamline the Department for Transport, Freeing Britain to Compete backs the closure of the Commission for Integrated Transport, which it describes as an advisory non-departmental body. Instead of relying on a single source of transport advice, the report says the government should turn to a wide range of think-tanks, universities and private industrial sources. It adds these should provide free access to the advice of all those pursuing a serious interest in public transport policy matters."