The Orange County Transportation Authority (OCTA) on Monday approved a $51.5 million contract to acquire eight S70 model streetcars from Siemens Industries Inc.

The units will be used on the future 4.1-mile Orange County Streetcar line, which will run from Santa Ana to Garden Grove, California. Six vehicles will operate on the system at a time, with two spare cars to be used as needed, OCTA officials said in a press release.

The contract includes the option to purchase up to 10 additional streetcars at a later date. As part of the agreement, Siemens will provide systems support and training to operators and maintenance technicians after the vehicles are delivered.

The S70 model units, which can carry up to 180 passengers, are operating in eight other U.S. cities, according to OCTA.

“We’re looking forward to making the vision for a modern electric streetcar here in Orange County a reality,” said OCTA Chairwoman Lisa Bartlett, who was elected to lead the board earlier this year.

In late 2016, OCTA released a request for proposals for the manufacturing and delivery of the eight streetcar vehicles.

The $299 million OC Streetcar project will be partially funded through Measure M, Orange County’s half-cent sales tax for transportation improvements. A mix of state and federal funding will cover the balance.

OCTA is working on planning and design with the Federal Transit Administration, which is considering a grant agreement to fund about half of the project’s cost.

Construction on the OC Streetcar is slated to begin later this year, with testing and operations beginning in late 2020.