A fire on an Amtrak maintenance train inside the Hudson River Tunnels caused major rail disruptions at Penn Station early Friday morning.Five transit workers sustained injuries during the blaze, which damaged overhead wiring and forced the suspension of Amtrak, New Jersey Transit, and LIRR services.Emergency crews contained the fire by early morning, but residual delays are expected to persist throughout the peak commute hours.Authorities are currently investigating the cause of the incident while commuters seek alternative routes into the city.