LAC-MEGANTIC, Que. -- Residents in the Quebec town of Lac-Megantic will mark the fourth anniversary today of the train derailment that killed 47 people and destroyed much of the downtown core.

There is expected to be a church service, an outdoor vigil and an activity at the town's train station.

The disaster on July 6, 2013, led to hundreds of millions of dollars in clean-up and reconstruction costs as well as the bankruptcy of Montreal, Maine and Atlantic Railway, the company that owned and operated the tracks.

As they rebuild, townspeople aren't dropping their calls for a bypass that would steer trains away from the town's core.

The Quebec and federal governments have financed a feasibility study on the matter, and the province's environmental review agency began public hearings on the issue in May.

But while policy-makers continue to look for ways to improve rail safety, Lac-Megantic is well into the reconstruction process.

Sonia Dumont, a spokeswoman for the town's rebuilding committee, says construction on several new projects, including a new park, pedestrian walkway and multi-functional community space, will begin this fall.

The town is also developing new "human infrastructure," including a new greeters program where citizens act as guides for tourists.

Meanwhile, three ex-railway employees are awaiting trial after pleading not guilty to 47 counts of criminal negligence causing death stemming from the tragedy.

Their trial is to be held in Sherbrooke instead of Lac-Megantic and is set to last from Sept. 11 to Dec. 21.

Conviction on a charge of criminal negligence causing death carries a maximum penalty of life in prison.

Montreal Maine and Atlantic Railway was charged with the three men and has pleaded not guilty to similar charges.

It will face a separate trial at a later date.