Abstract: Embodiments of collapsible wheels and methods of making collapsible wheels are generally described herein. Other embodiments may be described and claimed.

Abstract: Embodiments of collapsible wheels and methods of making collapsible wheels are generally described herein. Other embodiments may be described and claimed.

Abstract: A differential transconductance amplifier detects changes of the variable capacitor in a low-impedance, bridge circuit and feeds back current to balance the bridge. The voltage that controls the feedback current is proportional to capacitance over a wide dynamic range.

Abstract: An improved method is used to control the pressure in the brake pipe of a train. The train is equipped with an automatic brake handle, an equalizing reservoir, a brake pipe control device and a computer for controlling the control device according to position of the handle. The method involves the steps of: moving the handle to a point along its range of motion; and storing in the computer as a setpoint the value desired for the pressure in the brake pipe. At whichever point the handle occupies along its range of motion, there is a particular pressure setpoint corresponding thereto. The method next includes the steps of: directing the computer to command the control device to modify the actual pressure in the equalizing reservoir to the setpoint thereby also causing the actual brake pipe pressure to approach the setpoint.