Did you know that you can book some train journeys as part of an airline ticket and get elite qualifying segments and mileage out of it?
Wikipedia has a handy list of commonly-used train stations which have an IATA-assigned airport code. There is even a dedicated Flyertalk thread
The codes I most often use for my own searches are:
- ZWE – Antwerp Centraal
- ZYA – Amsterdam Centraal
Strictly speaking, you need to show your train ticket stamped by a conductor when you check in at the airport for a departure, but on the return sector the airline might find it hard to enforce checking you got onto a train …… !
Next time you're looking for flights, don't forget to try looking up some return or open jaw segments by searching some of the stations above. Sometimes you will find the train plus flight combination will be cheaper than just the flights alone!
(Thanks to Alvin)