Train transfer questions

I was checking the timetable for traveling from the Zurich Airport to Lauterbrunnen and noticed that the transfers between trains range from 3 minutes (Spiez) to 6 minutes in Bern and 7 minutes in Interlaken. This seems like a short period of time for a transfer. We will traveling with our luggage.
Is it reasonable to make the transfers in those cities going from platform to platform in that short a period of time?

I noticed that there were several stations listed for Lauterbrunnen. If I am staying in the middle of town, what station would I use? I do not remember more that one station in the town.

Thank you,

Rex

Rex
Check the timetable for platform numbers at http://www.sbb.ch/en/home.html. Click the plus sign on the left hand side for the train you want. It will give you the platform numbers.
In Bern the it is usually across the platform change so it is easy.
In Spiez it is sometimes across the plaform ( Platform 2 to 3) or if the train leaves from Platform 1 you have to go down a flight of stairs and then up another flight of stairs.
In Interlaken the trains to Lauterbrunnen leave from Track 2A. You always have to go down a ramp or stairs then up the other side via ramp or stairs
You should be able to make all the connections but it helps to know where you are going
In Lauterbrunen there is only one RAIL station. The others listed in the time table are bus stops and the BLM cable car.
Dick

Dick,
Thank you for the great information.
Rex