From the looks of straphangers during rush hour, with their headphones, smartphones, and e-readers, it would be easy to miss how old the New York City subway system is.

But every day, hundreds of trains run through the largest subway network in the world on century-old technology. When things go wrong — as they have been doing more and more often — the delays pile up.

The Metropolitan Transit Authority, a state agency responsible for the New York City subway, is fighting a budget battle to get the funds it desperately needs to update the century-old system. To garner public support, the agency took to YouTube a few months back, uploading video of the antiquated signaling system and what’s being done to update it.

A crucial element of the MTA's capital plan, the program that stands to lose the most funding from the state legislature, is Communications Based Train Control (explained below). The technology is revolutionary for a system as old as New York City's, and installing it on just one subway line took six years and $288 million to complete.

Scroll down to learn what's being done to improve a subway system that remains largely unchanged since its inception in 1904.

[An earlier version of this post was written by Graham Rapier.]