Zürich / Zurich to Hamburg by train

DB is the national railway operator in Germany, so its website can be used for booking journeys by German express trains; the ICE and IC trains and it doesn't charge booking fees.
It also sells tickets for journeys by direct trains on all international routes from Germany regardless of whether DB is operating the train service.

It also sells an extensive range of end-to-end journeys which involve making connections both within Germany and in neighboring countries, but journeys between Germany and Britain cannot be booked on DB.

A key feature of DB website worth keeping mind is that it offers 1st class ticket purchasers complimentary seat reservations on journeys both within and to/from Germany.
Seat reservations for daytime in both 1st and 2nd class can also be booked separately from tickets.

Two types of ticket have recently been made available;

1. Cheaper 'Young' tickets which can only be booked by those aged 15-26 on the travel date.
2. Flexi Plus tickets, which are now the most expensive type of ticket, but they're the only type of 2nd class tickets which DO include a seat reservation.

Happy Rail is a Netherlands rail ticket agency which sells tickets for both national and international journeys within a range of countries including Belgium France, Germany, Sweden, Switzerland.

HappyRail doesn't charge booking fees in the conventional sense, but if you're not Dutch you can expect to pay additional transaction fees, which will be added to the total cost.
That's because the most common form of online payment used in The Netherlands is 'iDEAL' and HappyRail doesn't charge a transaction fee for 'iDEAL' payments, but only Dutch residents can sign up to 'iDEAL'.
Other forms of payment include Visa debit cards will incur a fee.

OBB is the national rail operator and its booking service offers journeys by express trains within Austria, as well as international journeys which don't involve making a connection outside of Austria.

It pays off to book online, as the discounted 'Sparscheine' tickets are only ever made available on the website, and when making international journeys to and from Austria, these Sparscheine tickets tend to be cheaper.
OBB can offer particularly good value for money when travelling with children on international rail journeys, but something to watch out for when travelling between Austria and Germany on daytime trains, is that reservations are an optional extra; but if you book 1st class tickets with the Germany railways website DB, the reservations are complimentary.

OBB often takes a unique approach to its booking path, but a key thing to keep in mind is that the first price you will see for any journey is that of a Second Class seat.
The costs of upgrading to first class, a reservation, or a sleeping cabin etc, is then added to this price.

DB is the national railway operator in Germany, so its website can be used for booking journeys by German express trains; the ICE and IC trains and it doesn't charge booking fees.
It also sells tickets for journeys by direct trains on all international routes from Germany regardless of whether DB is operating the train service.

It also sells an extensive range of end-to-end journeys which involve making connections both within Germany and in neighboring countries, but journeys between Germany and Britain cannot be booked on DB.

A key feature of DB website worth keeping mind is that it offers 1st class ticket purchasers complimentary seat reservations on journeys both within and to/from Germany.

Seat reservations for daytime in both 1st and 2nd class can also be booked separately from tickets.

SBB is the main national rail operator in Switzerland, but tickets for journeys by the other significant operators including BLS and SOB can be be booked on the SBB website.

SBB also sells tickets for journeys to many destinations which involve a combination of SBB trains and services provided by the many independent operators who serve the Alpine resort towns.
However, if you will be making a long-distance return day trip, look out for he possibility of SaverDay passes being cheaper than tickets.

Though if you download the SBB app, booking tickets on SBB's mobile services can be simper than using the website.
Also watch out for the fact that booking international tickets can be comparatively quirky.