pretty sure this will work

you power it on, flick the cyan/pink/yellow lever to select the right fluid cell, turn the valve (it's redundant, sure, but you need to manually turn at least ONE valve ... it's more of a safety thing) and then flick the white/red lever to drain or fill the train from the selected fluid cell .....

I haven't tested it but it SHOULD work

had to add some more pumps but yeah, it works now. I can finally go to bed