"Get on" or "Get in"
It's easy to confuse using these phrases.
We can get on the train, an airplane, a bicycle, a horse, and so on.
We can get in a car, a taxi, a private airplane, etc.
So what are the rules?
If we sit on top of it (bicycle) or can walk inside it (airplane) we can use get on.
If it requires some effort or sitting position only (taxi) we use get in.
Hope this helps....