Enmax workers doing construction in downtown Calgary unearthed a small piece of the city's history last week.

While working on a substation located close to the CP Rail line, workers found a variety of historic tools and building materials buried beneath the dirt and gravel and subsequently stopped working and told archaeologists about the find.

The artifacts may date to as early as the late 19th or early 20th century, around the time period when construction began on the rail track that previously existed on the site.

"Significant historical items can often be found in old areas of major cities," said Michelle Wickham, a senior project archaeologist and partner at Bison Historical Services Ltd. "Unfortunately, when items are recovered they are not always handled as they should be, leading to either damage or total loss altogether. We commend Enmax for preserving Calgary's historical record in this way."

The tools were likely related to daily activities at the rail yard and were probably used for laying or replacing rail and railway ties.

They include pick axe heads, rail spikes and other miscellaneous items. A single brick was recovered with a shallow frog, likely hand-pressed, with the word 'Calgary' stamped into the frog.

Window glass and clinker, a waste matter separated from metals during smelting, were also recovered.

Enmax officials say they were surprised by the discovery and didn't fully understand their significance.

However, they have brought in an archaeologist to be on the site while the construction work continues.