SEPTA cab signal display for the 4-aspect PRR system using position light aspects. Pulse code cab signaling is a form of cab signaling technology developed in the United States by the Union Switch and Signal corporation for the Pennsylvania Railroad in the 1920s.
Measuring your Saddle Seat Size. The easiest way to measure for the appropriate seat size is to measure your upper thigh. Sit in a chair with your feet flat on the ground so that your knees are bent at a 45-degree angle. Be sure your buttocks are touching the back of the chair. Take a measuring tape and run it along your thigh bone, measuring from the end of your knee to the backside of your buttocks.
Both these traits can be measured. The muscle tissue can be biopsied and the heart measured with an ultrasound machine. The heart can also be measured with a heart rate monitor which tells you how hard a horse is working at a specific speed or workload. The GoPro Hero 3 Jockey Cam and HR monitors make a great pair. If a horse can maintain a high cruising speed and continue work out near the aerobic threshold then he would be an exceptional animal.