Droppin' some science

On a female helicopter the altimiter is to the left of the tachometer, on a male helicopter it's above it. That's the only way to tell. Automobiles are female if they have a license plate in the front and the back, and male if there's only one on the back. Automobiles have no gender if they have no plates. A brand new car straight from the dealership is sexless even with the paper temporary plates until it gets real metal ones. All ships are female unless they're spaceships in which case they're male if American and female if foreign, all submarines are male, and construction vehicles like bulldozers can have up to nine different genders for each make and model. Trains have three genders: those that run north-south are male, those that run east-west are female, and those that run northeast-southwest or northwest-southeast are primale. All high-speed trains with a maximum speed of over 200kph are primale regardless of vector.