One of Metro Rail's big benefits also presents one of its biggest challenges. It's mostly underground, never in the way. It quietly moves about 20,000 people a day out of sight. Millions of dollars in maintenance and enhancements? Those are mostly out of sight too.

For the last few years, Metro has been completely refurbishing all of its rail cars. 18 out of 27 have gone through a total frame-up restoration making them safer, smarter, more energy efficient and more reliable. Six rail cars are in various stages of restoration, leaving only three of the original design still operating. Even though the new versions have been greatly improved, all rail cars pretty much look alike.

The same is true of escalators. After spending $800,000 in new parts, they still don't appear very different. In fact, they work so well no one pays them any attention. Of Metro Rail's 19 escalator's, 11 have been selected for full parts replacement and eight for refurbishment. Five have now been through the process and function better than ever.

The last three years have seen track, bed and catenary wire replacements, as well as new power supplies. They are the most important parts of an electric light rail system. In the tunnels, they are almost completely out of public view.

Even when it's a visible improvement to Metro Rail the real benefits might be hidden. New LED lighting in the system provides the same safety and accessibility as always, but it uses considerably less energy.

A slate of rail enhancements will continue this year. Some will be more visible, like concrete work and fresh coats of paint. Others will remain behind the scenes, which is OK. In the end, Metro thinks they will show in the faces of happy riders.