Can you please check if these sentences are possible, please?

Thank you.

1)You can book your train journey online or through a travel agency.
First you make sure your passport is not out of the date.
3) Check the train time (time table?) and the fare.
4)Then buy your ticket and go on the platform. Punch your ticket before getting into the train.
5)If you have reserved a seat, make sure you get in the right carriage of the train. You can ask for a single or a return ticket.
6) You can book a two-berth compartment or a seat in first or economy class (Can you tell me the type of train tickets you can buy in America?)
7) Would you rather I went there by bus or on foot? Would you rather I made an appointment with the doctor today or tomorrow?
8) Is it all right if I close the door? Would it be all right if I closed the door? How can I reply? "Yes, of course/sure/certainly... Go ahead/OK
9) Could I close the door? Yes, certainly ("Yes, you can. Is it possible?)Do you mind if I close the door? No, not at all (is this the only possible answer?)When the doors are open you disembark (the plane???) and walk through the terminal building.

1) You can book your train journey online or through a travel agency.

First make sure your passport is not out of the date.

3) Check the train schedule and the fare.

4) Then buy your ticket and go on the platform. Punch your ticket before getting onto the train.
(Usually, the ticket is punched by a conductor AFTER you are seated and sometimes after the train starts to move.)

5) If you have reserved a seat, make sure you get in the right carriage of the train. You can ask for a one-way or a return ticket.

6) You can book a two-berth compartment or a seat in first or economy class (Can you tell me the type of train tickets you can buy in America?)
http://studenttravel.about.com/od/usstudenttraintravel/ig/Amtrak-Train-Photos-Gallery/Amtrak-Train-Tickets.htm
Scroll down to the list of links. There are coach, superliner, sleeper, family sleeper, and others.

7) OK

8) Is it all right if I close the door? Would it be all right if I closed the door? How can I reply? "Yes, of course/sure/certainly... Go ahead/OK
(All those responses are fine.)

9) Could I close the door? Yes, certainly (Yes, you can. Is it possible? YES) Do you mind if I close the door? No, not at all (is this the only possible answer? IT'S THE ONLY ONE THAT MAKES SENSE WITH THE NEGATIVE IN THE QUESTION.) When the doors are open, you can exit the plane and walk through the terminal.

Sure! Here are my comments on each sentence:

1) The sentence is grammatically correct. To book your train journey, you have two options: you can either do it online or go through a travel agency. It is important to make sure your passport is not expired before making any travel plans.

2) The sentence seems to be missing. If you meant to ask about the second sentence, it is advisable to include it for a complete understanding of your writing.

3) The sentence is grammatically correct. Before boarding the train, you should check the train timetable for the departure time and also check the fare to ensure you have enough money for the ticket.

4) The sentence is grammatically correct. After checking the timetable and fare, buy your ticket and proceed to the platform. Remember to punch your ticket before getting on the train.

5) The sentence is grammatically correct. If you have reserved a seat, make sure you board the correct carriage of the train. You can ask for either a single or a return ticket, depending on your travel needs.

6) The sentence is grammatically correct. In terms of train tickets in America, commonly available options include coach class, business class, and first class. However, the availability of different ticket types may vary depending on the specific train service.

7) The sentences are grammatically correct. In both cases, the speaker is seeking advice or a preference from the listener.

8) The sentences are grammatically correct. If someone asks for permission to close the door, you can reply positively by saying any of the suggested responses: "Yes, of course/sure/certainly... Go ahead/OK."

9) The sentences are grammatically correct. If someone asks if they can close the door, you can respond positively by saying "Yes, you can" or "Yes, it is possible." Similarly, if someone asks if you mind them closing the door, you can respond negatively by saying "No, not at all."

Regarding the last part of your question, without further context, it is unclear what specific doors you are referring to. However, if it is related to traveling and disembarking from a plane, it is common to use the term "doors" to indicate where passengers exit the aircraft and walk through the terminal building.