There is a way to use ether your Android (Engine Driver) or iOS (WiThrottle) device to control your model trains. Using JMRI RaspberryPi as Access Point you now have control of your layout from your phone or tablet.
Some more info can be found here.
Here is an open source base controller that can be used with JMRI called DCC++. It uses a ether an Arduino Motor Shield R3 or a Pololu Dual MC33926 Motor Shield to control your tains.
See also Model Railroad DCC Control - JMRI & Raspberry PI.
How to install JMRI and more on DCC++
Via HackAday
Links