Abstract: A tape drive for use in for example a transfer printing apparatus to drive a printer ribbon. The printer ribbon is mounted on two spools each of which is driven by a respective stepper motor. A controller controls the energization of the motor such that the ribbon is transported in at least one direction between spools mounted on the spool support. The controller is operative to energize both motors to drive the spools of ribbon in the direction of ribbon transport to achieve push-pull operations. Ribbon tension is monitored to enable accurate control of ribbon supply and ribbon take-up, the ribbon tension being monitored, for example, by monitoring power supply to the two stepper motors.

Abstract: A rail measurement system (10) for mounting on a rail vehicle (e.g., 12) for travel over a railway (16) having two spaced apart rails (18, 19) includes a first collimated light source (20) mounted on the rail vehicle for providing a first reference marker (22) relative to a first rail of the railway. The system includes a camera (28) mounted on the rail vehicle for recording an image of the reference marker relative to the first rail. The system also includes an image processor (50) coupled to the camera for analyzing the image of the reference marker relative to the first rail to determine a first rail alignment dimension (e.g., 39) with respect to the reference marker.