Which rails to buy a Lego Train?

Right now, two Lego Trains are on sale, the Passenger and Goods Train Train. In both cases it is worth buying this set of rails and a box of switches in addition to those with the passenger train.

The full range of Lego Train in 2014 includes:
- Train Passengers (Lego 60051)
- Goods Train (Lego 60052)
- Station (Lego 60050)
- Flexible Rails (Lego 7499)
- Switches (Lego 7895)

There are 4 different types of rails:
- The Switches (Left and Right)
- The Straight Lines
- Curves Lines
- The Flexible

The Passenger Train Rails contains 16 curves (enough to make 360 ​​degree circle) and 4 rights.
The Goods train contains the equivalent of passenger train over a box of switches.