"I think we've been singing 'I've Been Working on the Railroad' a couple of those hot days when we were out here," said archaeologist Bucky Buxton.
Buxton is singing rail tunes because he and his colleagues recently unearthed a treasure trove of Los Angeles rail history.
What is now being developed as the Los Angeles State Historic Park sits on top of the area's first railroad station, complete with yards, shops and round house.
In many ways the history of Los Angeles began at this uncovered railroad. Before 1880, Los Angeles was just a tiny farm town. Then, the railroad arrived.
"This rail yard was, to some extent, the Ellis Island of Southern California. This was the terminus. People coming from the east came here," said State Parks Director Ruth Coleman.
Remnants of the River Station, as it was called, include the redwood foundation for its historic round house. The round house is where steam locomotives were serviced and rebuilt. The brick foundations for shops and grease pits were also found below the ground.
"I'm amazed at how much is still here that has survived. And, of course, the more we excavate, the more we're finding," said Buxton.
As L.A. boomed, it quickly outgrew the River Station. So, the buildings were carted across the river. The old one was covered and then turned into a new rail yard.
At one time, 90,000 freight cars were loaded and unloaded at the rail yard each month. In those days, prosperity rode the rails.
"We had this huge agricultural boom, then the oil industry hit ... In fact, Standard Oil was just up the road here from this ... their first refinery. That kind of wealth allowed it, when the turn of the century, you know, you got the movie and entertainment industry. Los Angeles was just primed to take off," said State Parks Historian James Newland.
Archeologists can't uncover everything that lies beneath the park. However, they say what they've found will be left intact.
When state officials unveil final plans for the park's development, the items will be open for all to see.