If I were fabricating something, I would go with electro-mechanical. The switch on my '57 LCF is still working, the pressure switch on my Harley is NOT working.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy