NEW CANAAN — When the trains stop, Uber will be there, and at a discount.

Ride-hailing service Uber will run a promotion for commuters moving between New Canaan and Stamford railway stations through Aug. 21 in response to service interruptions.

Because of grade crossing renewal work and maintenance at New Canaan Metro North Railroad stations during this time, service between New Canaan and Stamford will be limited on Fridays and suspended completely on Saturdays and Sundays.

While service is interrupted, Ubers called from anywhere in New Canaan heading to or from the Stamford Raiload Station on Fridays starting at 6 p.m. through Monday morning at 2 a.m. will receive $10 off. Each rider can use the promotion up to four times.

According to an Uber spokesman, if construction continues, the promotion will be extended.

Metro North is also providing alternate service while construction is underway. Substitute buses are scheduled to run hourly between New Canaan and Stamford stations. Metro North notes that buses will run 15 to 20 minutes earlier than scheduled trains. For a full schedule, visit http://web.mta.info/mnr/pdf/NewCanaanBus_714.pdf

justin.papp@scni.com; @justinjpapp1