200kmh/h is the generally accepted threshold for high speed rail. EDIT: from the UIC website: "In any case, high speed is a combination of a lot of elements w

200kmh/h is the generally accepted threshold for high speed rail. EDIT: from the UIC website: "In any case, high speed is a combination of a lot of elements which constitute a whole "system": infrastructure (new lines designed for speeds above 250 km/h and in some cases, upgraded existing lines for speeds up to 200 or even 220 km/h),..." http://uic.org/highspeed#What-is-High-Speed-Rail http://uic.org/highspeed#What-is-High-Speed-Rail