At least the hammers I see (on European trains and buses) have a sharp, conical tip. There are usually instructions to hit the window close to the corner. See

At least the hammers I see (on European trains and buses) have a sharp, conical tip. There are usually instructions to hit the window close to the corner. See the picture on https://en.wikipedia.org/wiki/Emergency_hammer https://en.wikipedia.org/wiki/Emergency_hammer (The wording in the Wikipedia article is not clear. Do American trains really not have these?)