Not sure if this is an odd question but how do train genders work? Like is it separated between engine, coach and freight. And would appearance as male or female like a second gender to them since any of them could have any kind of human gender presentation?
According to the National Registry of Rolling Stock Personnel, they’re officially separated into three categories which are male, female, and neutral, determined by which secondary sex characteristics they manifest in secondary. Male and female are pretty self explanatory, but neutral is a very broad category developed in the 1950s in order to organize what humans would consider now as visibly trans/non-binary rolling stock. Basically, if you have a mix of secondary sex characteristics and/or have transitioned at some point in your life, you’re considered “neutral” by the government. Rolling stock almost never use these terms for themselves, if they are even aware of the Registry’s existence.
Because if asked the question of “what are you?” in reference to gender, most rolling stock would probably misunderstand and state what type of equipment (diesel engine, dining car, bulkhead flatcar, etc) they were instead. It’s not that they’re laissez-faire about gender, that is still important. No one likes to be misgendered. But I don’t think it’s the most load-bearing facet of their identities as a whole. They are sexless machines after all.
Some of them do mentally connect their gender to their rolling stock type (although I wouldn’t say it’s common or unproblematic - Greaseball calls himself a diesel engine but what he really means is that he’s a man’s man) and others, not so much (Rusty is a steam engine first, and a man second).
Basically, to rolling stock, gender is gender and type is type, ranked separate and slightly higher. The only rolling stock type that has any sort of bias to a specific gender presentation are steam engines who, contrary to popular belief, skew female, or at the very least, femme-presenting. But again, not a very important characteristic to them.
I personally never liked, or even really considered, that type was linked to gender as a hard rule across every piece of rolling stock. Even though in show canon, we see some overbearing, and questionable, organization of genders, I always thought that the cast of characters were just a slice of this universe, and that there were more trains of every kind of presentation that we weren’t seeing. There are literally millions of rolling stock worldwide, the 25-30 people we see in Starlight Express do not represent the whole. There are plenty of masc presenting passenger cars, and femme presenting freight cars and engines (and every gender presentation in between of course!)