GRADE CROSSING FLASHER
 
- suitable for a grade crossing
- outputs for alternately flashing LEDs as warning lights
- output for single flashing LED as free crossing
- power supply: 6-15V DC
- polarity protection
- input for a switch, reed relay, or infra gate
- flashing frequency: 1 Hz
- suitable for lights with common anode
- output voltage: same as the input voltage
- output current: 400mA / output (altogether 1200 mA)
- size: 30 x 22 mm (1,18" x 0,91")
- the LEDs are not included
 
After the power supply is switched on, the single flashing light starts flashing as a free gate (if used). If the input pin (pin S) is connected to the ground (pin 0), the warning lights start flashing. 
 
Adding the universal NPN transistor (2N2222, BC547 or similar) you can simulate the "Do not Stop on Track" US version of grade crossings. Many thanks to John Bauchiero for this upgrade.
 
Video: here