Add highlight background to preferred train row

Adds a slight highlight to the preferred train row
Change highlight color as needed
![screen shot 2014-08-24 at 8 43 02 am](https://cloud.githubusercontent.com/assets/1044502/4023396/d08eb354-2b8c-11e4-87ed-cec757d25469.png)

http://i.imgur.com/LttpY3i.png