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Why the special air intake duct? Does the railroad have a lot of tunnels?
The special air intake duct reminds me of the old "tunnel motor" SD45's and SD40-2's made for the Southern Pacific and the Rio Grande by EMD in the 70's. They were designed so cool, fresh air from the floor of a tunnel entered the engine from the walkway instead of hot air and exhaust trapped at the roof of a tunnel entering the engine through its roof.
I like how the newest demo unit incorporates the green and yellow of the Brazilian flag in the paint scheme.
Bill, yes MRS has a lot of tunnels in its ore corridor. Some are big, like "Tunelao" with 8.640 meters long. But the worse one is Cabrito tunnel. It has 997 meters long, a big grade and just 8% of oxigen inside. This tunnel is the terror of the engineers. Some serious accidentes happened there. In the past the tunnels had wooden gates to help refrigerate the locomotives, but with the advent of GE AC44's, the gates were removed. But this tunnel proved to be a terror to EMD SD70ACe's. They failed when leading ore trains through it. That's why MRS refuse to buy SD70ACe from EMD. So EMD decided to modify a SD70 and build a SD80 with special air intake system to test with ore train through Cabrito tunnel and others ones along Ferrovia do Aço (we call it "FA" only).
Note that this modification is totally diferent from the tunnel motors in SP era. Those diesel engines had special devices to collect air to the radiator fans, not to the diesel engine as we see in this pair of Demonstrators produced to MRS.
Why the special air intake duct? Does the railroad have a lot of tunnels?
The special air intake duct reminds me of the old "tunnel motor" SD45's and SD40-2's made for the Southern Pacific and the Rio Grande by EMD in the 70's. They were designed so cool, fresh air from the floor of a tunnel entered the engine from the walkway instead of hot air and exhaust trapped at the roof of a tunnel entering the engine through its roof.
I like how the newest demo unit incorporates the green and yellow of the Brazilian flag in the paint scheme.