The ore trains at Ferrovia do Aço, pulled by diesel-electric locomotives, had to cross some big tunnels, like the Tunelão ("Big Tunnel"), with 8.645 km (approximately 5,4 miles) of length. Like all other tunnels at this railroad, this one has not special ventilation devices - well, this railroad was originally designed to have electric traction! So smoke generated by the diesel-electric locomotives when the heavy iron ore trains cross this tunnel can not be efficiently exhausted. Besides that, the ambient temperature inside the tunnel increases and eventually can force locomotive engines to stop. In the case of Tunelão this problem is even more serious, as loaded iron ore trains, Rio de Janeiro bound, have to face a slight ascent. This could be a nightmare: train crews inside stalled trains being poisoned by dangerous smoke...

This problem was overcome with a ingenious solution: a wooden door covers the tunnel exit while the train is crossing it. This prevents air to exit from the tunnel by this opening, forcing it through the tunnel; as it mets the locomotives, it carries behind the poisonous combustion gases. The door is made of wood, so if someone forgives or fails to lift it when the train exits from the tunnel, the door is destroyed without significant damage to the locomotives. This is what we call jeitinho brasileiro ("the Brazilian big easy")!

This photo shows an iron ore train exiting from Tunelão. One can see the wooden door lifted at the tunnel exit, a control cabin and, helas, the huge amount of smoke evolving from the tunnel! Photo shot in September 1998 by José Henrique Bellório, from Bauru SP.