reliability

The quality of being reliable, dependable, or trustworthy.

Above all, rail needs to be boring. By that, I mean that it must run its timetable reliably, day-in and day-out. Punctuality and reliability remain the bedrock of a successful railway.

the ability to measure the same thing consistently (of a measurement indicating the degree to which the measure is consistent); that is, repeated measurements would give the same result (See also validity).

measurable time of work before failure