An estimated 150,000 commuters into and out of New York’s famed Grand Central Terminal faced crippling delays Wednesday, one day after a raging fire broke out beneath elevated train tracks in the city, officials said. The blaze Tuesday night at a garden center underneath Metro-North tracks north of the station in Manhattan’s East Harlem section halted train service and left thousands of commuters stranded on their way home. Metro-North said two of the four tracks in the area of the fire were operational for Wednesday’s morning rush. Trains were slowed from their normal 60 mph to 30 mph as repairs continue.