If the engineers do walk off the job, the agency plans to increase bus service, saying it would add “very limited” capacity to existing New York commuter bus routes in close proximity to rail stations and will contract with private carriers to operate bus service from key regional park-and-ride locations during weekday peak periods.

NJ Transit and an engineers’ union appear to be heading toward a major rail strike that would start Friday — the first one in decades. Currently, both sides are in Washington, D.C. participating in mediation,