今電車の中なので、あなたと電話で話せないって英語でなんて言うの？

It's often rude to talk on the phone while riding on the train in Japan. This can be distracting for other passengers. It is also not the most convenient place to have a private conversation since there are usually many people onboard who are able to listen into your conversation. Therefore, when receiving a call on the train you can tell the person who called that you're on the train and make an arrangement to call him/her back later.

Because you may not want to broadcast your private conversation to all members of the public on the train with you, your message should be short and concise. If you use the example message, the situation will be understood by the listener.

I am on the train right now, I will call you when I am off - This is a easy way to tell someone you will call them back once you're off of the train. I cannot answer your call right now because I am on the train. - This tells them why you did not answer their phone call but does not imply you can call them back immediately I will call you back when I am off the train - This is very casual and tells them you will call them as soon as you get off of the train.

When you want to apologize to someone calling you because you cannot speak; then you may explain in the following ways: -I can't talk right now because I'm on the train. I'll call you back. -Let me call you back in a few minutes. I can't talk because I'm on the train. -I can't talk because I'm on the train

In many countries it is considered rude or impolite to be talking while other people are silent, like on trains, in the post office, or in public places especially where people might be reading or concentrating. We can explain this to people by informing them that it is considered impolite to talk on the trains in Japan because it may bother the other passengers, therefore, when I am riding the train, I can not talk on the phone. If you would like to not explain and simply state, "I am unavailable when I'm on the train." Some people might understand without any explanation. Also because there is usually an insecure signal on the trains, so call reception may not be optimal. For many reasons you can simple express, "I am not able to talk when I am on the train.."and people can imagine the reason.