LOS ANGELES (CNS) — Metrolink will shut down for four days toward the end of the year so workers can clean and repair trains and upgrade the regional rail network, officials announced.

Metrolink trains will be out of service from Dec. 26-29, and will resume regularly scheduled service on Dec. 30, the agency said on its website.

The closure applies to the entire Metrolink system, including the Arrow service.

The break will allow Metrolink to implement a new signal system for improved operational efficiency and reliability, especially at Union Station, officials said.

Metrolink is not providing alternative transportation.

Riders who purchased a monthly pass were asked to contact the agency’s customer service team for refund requests at metrolinktrains.com.

LA Metro buses, the subway and rail lines will continue normal operations during the closure.