MBTA OFFICIALS ON MONDAY outlined a series of investments and maintenance strategies that should dramatically improve service for the transit authority’s subway riders over the next five years. Many of the steps were previously announced, but a presentation to the Fiscal and Management Control Board packaged them together in a way that showcased how riders on the Red, Orange, and Blue Lines will soon enjoy much faster service on trains that are less likely to experience delays and breakdowns. The Red Line, which currently serves 281,284 passengers on a typical weekday, will see the biggest change. The existing 210 trains (with an average age of 34 years) will be replaced with 252 new cars. The new cars will help cut the interval between station train arrivals from 4.5 minutes to 3 minutes during peak periods, and allow the Red Line to carry 50 percent, or 140,642, more passengers. [CLARIFICATION: I checked with the T subsequent to publication and their spokesman says the interval between station train arrivals is 9 minutes on the Braintree and Ashmont branches of the Red Line and that falls to 4.5 minutes when the branches merge at JFK/UMass.] On the Orange Line, the T plans to replace the existing 120 cars (each 38 years old) with 152 new cars. The new cars will help cut the interval between station train arrivals from 6 minutes to 4.5 minutes, and allow the Orange Line, which currently carries 203,442 passengers on a typical weekday, to add 81,377 more riders. The T is spending more than $1 billion on the new Red and Orange Line trains, which will start arriving next year and be fully deployed by 2023. The T is not planning any major expenditures on the Blue Line, which has 94 trains with an average age of 12. But the T nevertheless is planning to cut the interval between station train arrivals from 4.5 minutes to 4 minutes and to expand the line’s capacity from 69,475 passengers on a typical weekday to 86,844. Although the T’s subway ridership is currently growing at about 1 percent a year, Transportation Secretary Stephanie Pollack said the huge investments in expanding capacity on the Red, Orange, and Blue Lines are warranted. “We are sizing the fleets assuming we will have more riders in the future. Exactly how many more riders, that’s an iterative process,” said Pollack. “Traffic is not getting any better, population is up, jobs are up, which is all great.” Polllack said she and Gov. Charlie Baker believe demand for subway service will grow if the T delivers a good service. “We saw this in the ridership data. Peak service on the heavy rail lines is the least susceptible, at the moment at least, to competition from transportation network companies. You’re never going to be able to  move as many people as the Red Line with individual cars, whether they’re autonomous, electrified, or transportation network companies. This is the place where transit is the most competitive in a dense, growing region and we should be building capacity.” The MBTA is also planning significant upgrades to its subway power and signal systems, which are akin to traffic signals on roadways, and revamping the way maintenance is done on vehicles. Instead of running vehicles until a problem arises or until funding is found for a midlife overhaul, T officials said they are adopting a new approach that attempts to forecast maintenance needs and address them on a scheduled, ongoing basis over the life of the vehicle. Jeffrey Gonneville, the T’s deputy general manager, said the transit authority has been devoting about 80 percent of its maintenance resources reacting to problems and about 20 percent on getting out ahead of repair problems. Gonneville said the T is hoping to flip those percentages by adopting what he called a reliability-centered maintenance philosophy, which attempts to forecast maintenance needs and address them on a continuing basis. T officials said they are using the new maintenance philosophy on the Blue Line with the expectation that it may increase operating costs for maintenance in the short run but lower overall maintenance costs in the long run by avoiding costly train overhauls. The Blue Line cars will only need a $54 million “light overhaul” between 2019 and 2021, the officials said. Bill Griffiths, the T’s senior director of fleet strategy, said preventive maintenance relies heavily on technology. He noted that the new Red and Orange Line vehicles will be equipped with on-board maintenance systems that will signal when repairs are needed. Griffiths also said the T plans to spend $499 million over the next few years expanding and modernizing the maintenance facilities for the Red and Orange Line trains, which should allow the rail cars to be repaired more quickly and efficiently. Gonnveille said maintenance work may sound technical but it can have a big impact on the subway’s reliability. “What we did on the Blue Line [with reliability-centered maintenance] had a tremendous effect in improving the reliability of the fleet itself,” he said.