Why does it matter?
Although you have posed a legitimate question it also begs the question to be asked of, "why does it even matter?" Which, personally, I find to be a much more compelling question.
We all have a need to be validated and liked. It's part of our social fabric and perhaps, part of our DNA. We are a social animal and to be liked increases our chances of mating and continuing our genetic material. Continuity is a key component and driver for every animal species on the planet. We eat so we can grow so that we can mate. It's as a simple as that.
Underlying that matrix of drivers is a desire to be liked. If others approve us then a possible mate will see our 'approval rating' with our social group and possibly consider engaging in mating in order to pass on their genetic material, together, you both move onto the sunset doing whatever your specific species does with offspring.
So ultimately, why does it matter?
Well, we want our families to accept us. It gives us the validation we require in order to show confidence. Confidence is an import aspect of roaming the planet. It allows to attempt to do things we may not have otherwise. Plus, these our individuals that are frequently part of our daily routing and their acceptance drives our own self esteem which again is a key component of confidence. It only makes sense that you would strive for the acceptance. You show many of the signs of low self esteem. You promote your activity as an active agent of the activity. This, in many studies, is off putting. Especially if the individual being advertised the activity is completely uninterested. Your lack of interest in others activity, you mention sports, shows a privileged position of entitlement. Your not interested in your families activity and you actively demote the credibility of what they enjoy yet you expect acknowledgement. Expecting something is a clear sing of being entitled. This is a dangerous place to be in the mating game and the behavior can spill into a lack of attractiveness that may inhibit your ability to consummate intercourse and complicate your active desire and need to mate and continue your genetic material into the future.
It's curious that you would want to contaminate your professional landscape with a personal love and hobby. It would seem that simply talking about how you love trains for a short period of time at lunch with new individuals would be enough for you to advertise that you are interested in the topic and allow people to gravitate to you at will rather than an active and energetic advertisement of your passion in a break room. You may be setting yourself up for disappointment if you are unable to attract others with your passion. I would imagine the demographic of train'o'philes is rather small per capita and you may not have a large enough statistical population base to find someone of similar beliefs.
This could be dangerous for your self esteem and confidence at work if others do not engage in your level of passion. You may end up feeling isolated and possibly humiliated if an aggressive alpha were to tease you in front of someone you like. This could cause irreparable confidence issues for you at work which is a place where confidence would typically be a key ingredient for success.
A Different Approach
I would suggest finding a club where there are people as passionate as you related to your subject matter. You will find a group if you search. This will allow you from attempting to 'turn' people in your life into passionate train buffs and allow you to completely disengage from the emotion hurdle of gaining acceptance in that fashion.
You can then focus on the positive aspects of what you love and enjoy with people who also love and enjoy your passion. You will not have to deal with the fear and anxiety of gaining others acceptance of the hobby as legitimate because you will be surrounded by people who legitimize the hobby by simply showing up to share their hobby.
I hope this helpful to you and I hope you understand the message I am attempting to convey in my feeble words. You are worth more than chasing acceptance. Go to where you will find it and you will thrive.