The short answer is: no. A derailment can be caused by many factors, some of which are not directly related to the wheel-rail interface. If we take the design of a roller-coaster that can be held in any orientation, for example, these designs are not proof against derailments. Derailments can be caused by problems in many areas: - Railcar: wheels, bearings, bearing adapters, sideframes, bolster, springs, wedges, centre plate, structural failure, braking system (locked on). - Track: rails, ties, roadbed, debris. - Other: high speed, switch set incorrectly, other vehicle on track. In fact, derailments are fairly common, but since most of them happen at low speeds, affect only one or two cars, and are easily remedied, they pose no threat and receive no press. A minor derailment might be rectified by a crew of three or four people in an hour. However, because a train contains a very substantial mass of steel, any accident at speed will cause a correspondingly large amount of damage. Since railcars are used to transport a wide range of products, an accident may pose secondary health risks, such as the wreck that caused authorities to evacuate a large part of the city of Mississauga in 1979. ------------------------------------------------------------ Re: "Then how would a Maglev derail?" Roadbed damage, collapse, or obstruction; excess speed; separation of railcars; mechanical failure causing loss of control; electrical failure causing loss of control or loss of repulsion; collision; driver error. It's not hard finding ways for mechanical or electro-mechanical systems to fail. The more complex the system is, the higher the probability that a fault will cause a serious problem. The faster a system is, the less control the operators have when a problem occurs. Very few people die in collisions between two walkers. Very many die in collisions between two drivers. As the system increases in speed and complexity, the probability that a small error or minor fault will produce a catastrophic end result increases. I fall down and crack my knee; airplane falls from sky and 300 die.