Subway and bus riders were frustrated Sunday by the first day of the doomsday transit cuts, but the pain will likely get worse Monday, when the bulk of the service changes hit the system.

“This is ridiculous,” said Urlah Valentine, 52, a Brooklyn rider, who walked for blocks Sunday after two buses she regularly took — the B39 and M8 — were cut.

Straphangers across the city stared with disbelief Sunday at bus stop signs detailing the cuts, or waited for service that never came. For example, riders on the B64, which used to go to Coney Island, stood in the hot sun to transfer to a different bus to the beach, and parishioners from the Saint Stanislaus Church on East 7th Street struggled to figure how they would travel west without the M8 bus.

“They should’ve been handing (information) out in the subway,” said Rose Kerr, 60, a Bronx rider who waited 20 minutes for the M50 bus before a reporter told her it is no longer running on the weekends.

advertisement | advertise on newsday

Rush hour straphangers will face additional burdens today with the loss of the W line, the discontinuation of the M train into south Brooklyn and more crowded trains across the system.

“People will have tough day of commuting ahead of them,” said Gene Russianoff, of the Straphangers Campaign.

The cash-strapped agency, which is facing an $800 million budget gap, is eliminating or scaling back more than 100 bus routes and three train lines to save $93 million a year.

"These reductions, while painful to our riders who will be inconvenienced ... are nonetheless necessary," a NYC Transit spokesman said.

Katherine Lieb contributed to this story.