The MTA’s upgrade to its train signal system continues – this time on the A, C and E lines.

“I take the A almost every day, and it runs express, so it’s going to have to mean longer trips,” A train commuter Charles Scheiland said.

Uptown A, C and E trains are on normal schedules, but from Tuesday through Friday, downtown A trains will run express from 59th St-Columbus Circle to Canal Street at all hours; downtown C trains are express from 145th Street to Canal Street; and downtown E trains will run on the M line from Fifth Avenue-53rd Street to West 4th Street-Washington Square.

On the D line, downtown D trains will run local from 145th Street to 59th Street-Columbus Circle. During rush hours, select D trains will run on the E line between Roosevelt Avenue and 47th-50th Streets/Rockefeller Center.

For Brooklyn-bound trains during morning rush hour and Queens-bound trains during afternoon rush hours, M trains will run on the J and Z lines between Delancey-Essex and Chambers streets, and M trains will stop running at Chambers Street and will not run between Essex Street and Forest Hills-71st Avenue.

The transit agency is replacing switches and tracks with more modern, computerized technology.

The 7 and L lines were among the first to have this work performed as part of a series of signal upgrades that will modernize the train system. The MTA expects they’ll lead to faster, more reliable service with a smoother ride and more predictable arrival times.

The agency says it’s doing the work during the President’s Day holiday week, when ridership is historically lower, to inconvenience as few customers as possible.

But commuters like Scheiland, who takes the A train all the time for work, say the inconvenience is unavoidable, even on a good day.

“I find that the A runs less frequently than other trains,” Scheiland said. “Like on a good day, the A is almost every eight minutes, whereas the 1, 2, 3, it would be like every 4 (minutes).”

This coming weekend, there are also service changes to several lines.

The MTA says the “Service Status” box at new.mta.info is always the best source for the latest status of each line.