I'm looking for a train in Cambridge that will arrive by 18:30
Are you leaving Cambridge or going to Cambridge? Better yet, what is your departure city and destination? 
I'm departing from cambridge and would like to go to norwich on a monday.
Yes I have the 17:55. May I help you with anything else?
If it arrives by 17:55, then yes, please book 1 seat for me.
I was able to book TR8504 leaving cambridge at 16:36 arriving norwich at 17:55. The total fee is 17.6 GBP and your reference is P5JNVZHA.
Fantastic, thanks.  I'd also like to find an architecture attraction in the centre of town, please.
I have about 5 different options for you. Most have free admission, except one. Might I suggest the All Saints Church on Jesus Lane. It has free admission. 
Can I get the postcode for that please?
all saints church's postcode is cb58bs.
Thank you! That is all the help I need today.
You're very welcome. I do hope that you enjoy your trip. Goodbye.