Harrison's day begins on Halstead Avenue, with the platform lights on and the first train pulling south. BH Lawnscape Inc is usually out ahead of the commuters, mowing and edging the lawns of a town that keeps its front yards trim and its maples tall. The work follows the Westchester calendar — a first cut when the ground finally dries, mulch and bed lines in May, a last pass when the leaves outnumber the blades. A boundary so clean it looks drawn with a straightedge is its own kind of proof. By the time the evening trains come back up the New Haven line, the grass stands straight and the walks are swept.