An artist's impression of an Edinburgh tram in action

French company Alstom and Spain's CAF are up against German-based Siemens and Bombardier Transportation, a German arm of Canadian giant Bombardier.

If the tram bills are passed by the Scottish Parliament, a decision will be made on the tram supply tender by the end of the year.

The firms have all been involved in designing trams around the world.

Smooth acceleration

Officials at Transport Initiatives Edinburgh (Tie) said they will be looking for trams designed to make as little noise as possible, which have smooth acceleration and braking, multiple and wide doors to enable easy boarding and alighting.

The council-owned company also wants low floors and level boarding at all passenger doorways, security features such as CCTV and emergency call points, public address systems and room for at least 200 passengers per vehicle.

Ian Kendall, Tie's project director, said 11 firms originally indicated interest, with seven bidding for the opportunity to tender.

He said: "This is an important step towards the delivery of a world-class tram system for our capital city.

They are a glimpse of the exciting future ahead when trams are an effortless part of our lives Donald Anderson Edinburgh council leader

"Over the next few months, we will be scrutinising the bid information from each of these four firms to ensure that we get the best deal in terms of quality specification and value for money.

"All of the companies chosen by Tie to tender have a wide portfolio of products, have worked previously in the UK and are able to supply vehicles which meet our stringent requirements."

Donald Anderson, Edinburgh Council leader, said: "Each of these companies provides a high-quality choice for our new tram system.

"They are a glimpse of the exciting future ahead when trams are an effortless part of our lives whether we are travelling to work, the shops or a rugby match."

The proposed tram network has been scaled back with just one line from Leith's Western Harbour to Edinburgh Airport now included in the first phase of construction.