"I will come by the train" vs. "I will come by train" - do we need the article here?

I will come by the train.

Is it correct or we need to remove "the". Give reason also.

Answer

When referring to a mode, the article is omitted:

They arrived by boat.

We will ship this item by air.

We will go there by train.

The politician communicated with his base by tweet.

The train conductors union is on strike so we will have to go by bus.