The expression of interest stipulated that the trams had to be low floor, to comply with the Disability Discrimination Act, that 40% of the total contract was to be local content, and that the first were to enter service in 2012.

The invitation to tender stated the contract had been declared a strategic project, requiring a minimum 25% local manufacturing content, and 50% local content over the life of the contract, with 150 jobs expected to be created.

[6] In September 2010, Bombardier was awarded a contract for 50 Flexity Swift low-floor trams, including maintenance to 2017.

[14][15] A two-thirds mock up was produced for design input, and was unveiled on 24 August 2011; it was displayed at the 2011 Royal Melbourne Show.

[14][16][17][18] A seven-month delay in delivery was announced in August 2012, with Bombardier stating that design complexity had slowed down construction, and the E-class would be operating from July 2013, with the last tram to be delivered in 2018.

[36] The redesign implemented measures such as glare reduction to allow improved road visibility for drivers and extra handholds and grab rails for passengers.

The swivelling bogies are enclosed by a "wheelbox" under seats in the passenger area, allowing the tram aisle to remain low-floor throughout.

Other models of Bombardier's Flexity Swift tram of comparable length have four motors with each providing from 120 to 150 kW (160 to 200 hp), however the E class has 6 × 105 kW (141 hp) motors powering three bogies with one bogie unpowered.