This report provides an update on the state-of-the-art technologies with intrusion and obstacle detection capabilities for rail rights of way (ROW) and crossings. A workshop entitled Intruder and Obstacle Detection Systems (IODS) for Railroads Requirements was held in 1998, and the Volpe National Transportation Systems Center published the proceedings in 2001. A suite of possible alternative detection technology systems were then field-tested; the results were published in 2003. A host of novel approaches to detection involving existing and emerging technologies have since appeared. This report identifies these new non-track circuit-based approaches and methods of identifying obstacles and intruders on the ROW and at crossings. The results obtained from thisanalysis provide a technology update for the Federal Railroad Administration, as well as recommend potential technology conceptsfor future field testing. The application of intrusion and obstacle detection or remote sensing technologies would serve to improve the safety of rail passengers and road users, as well as protect the general population and environment from the risks associatedwith hazmat shipments, and aid in the relief of congestion by reducing the number of incidents and delays due to those incidents.