San Luis Obispo Fire crews are in the cleanup stages of a major fire involving several rail cars this morning near Orcutt Road and Laurel Lane. Officials say the first call came in at about 3:30 a.m.. Five train cars filled with used railroad ties were involved. Rail service is expected to be shut down for most of the day. No streets have been impacted by the blaze which is being called suspicious. An investigation is ongoing.