09/27/2013 01:49 EDT | Updated 11/27/2013 05:12 EST

What's in rail tankers and why can't we know?

Nearly three months after the  Lac-Mégantic disaster, rail safety remains at the top of the national agenda with a meeting of federal and provincial transport ministers this week focusing on the question of what is in tanker cars and why provinces and municipalities can’t get that information.​

- What's in those rail tankers?

- Safety rules lag as oil transport by train rises

- TIMELINE: Lac-Mégantic rail disaster

- Faces of the Lac-Mégantic tragedy

were gathered in Winnipeg, 17 Canadian National rail cars  some carrying flammable petroleum, ethanol and chemicals  came off the tracks near the village of Landis

climate and energy campaign coordinator for Greenpeace, says there is resistance by the shippers about releasing that information.