Moffat Tunnel

[Anonymous]

when i went skiing at winter park last year, i took the wonderful oppertunity to take pictures of the west portal of the Moffat tunnel, and there are several things i am curious about.
1. there is what looks like a small radio antenna with wires leading into the tunnel, am i correct in assuming that it is a repeater for trains in the tunnel?
2. as i moved closer to the tunnel, i heard the distinct sound of an air hose bleeding off air, but it was steady, and did not let off, and was still there the next day. What is this?
3. i have heard rumors of a "door" closing off the east portal except when a train is passing. if this is true, what is it for, how does it work, and how is it activated when a train nears it?
thanks in advance for any information.

[Anonymous]

At the East Portal, there is a gate, or "curtain", that raises when a train approaches and lowers after the train passes. This is part of a ventilation system for the tunnel. However, I have heard that since the UP takeover of the former Rio Grande trackage, that traffic on the line has increased to the point where the door is left constantly open. I'm sure that it is controlled automatically by CTC. It opens and closes like a garage door, rolled up and down from the ceiling. The wires that lead into the tunnel probably go to the telephone safety stations inside the tunnel. Others, most likely concern radio transmissions for trains while in the tunnel. I'm not quite sure about the air noise. The door at the East Portal used to be red and white striped. I'm not sure what color is is now. Probably black. The tunnel was completed in 1927, and is exactly 6.21 miles long, a straight bore. Before its completion, the railroad twisted its way up to eleven thousand feet, where it crossed the continental devide at Rollins Pass. The old grade also included a loop at Rifle sight notch, on the East side of the Summit.

[Anonymous]

The door on the east end is still used and is red and white with a big UP logo. As a train enters the west end big blowers start to run on the east end and as the train gets near the east end the blowers shut off and the door opens, after the train passes the door closes and the blowers run for 15 to 20 minutes before the next train can enter, that is why the moffet line is so slow. Not sure about the wires they may be relays for ETD and DPUs as well as for emergency phones.

gwl
http://photosbygreg.20m.com

[Anonymous]

Can you here the train if you on one end and the train on the other.Or can you see the headlight if the tunnel is straight like you say.

[Anonymous]

No. From the east end the door does not open until the train is almost to it. from the west end it looks like the train is more than half way before you can see its lights and even closer before hearing it.

gwl
http://photosbygreg.20m.com
updated 3/30/02

[Anonymous]

the antenna and wires are repeaters for the rear end devices and the DPU's, also a radio repeater.
the air sound was probably the sound of the exhaust fans but I'm not certain that is what it is.
there is a door at the east end. It is there because as the train goes into the tunnel it acts like a piston, driving out all the air in front of it and of course leading to lot's of problems. As you read in some of the other answers, there are huge blowers that blow out accumulated exhaust gases from the tunnel, these are on from the time the train enters until 20-30 min after each train. they work in conjuntion with the curtain to ensure enough fresh air in the tunnel for the crew and the engines to work. As to the activation of the curtain, it is tied in with the signal system like an interlocking, if the curtain doesn't work the crew gets a red signal and has to stop until they can get the curtain up.
Also, one of the other replies said something about the tunnel being straight, this is true, but it is not level, the peak of the climb is in the approxamite middle of the tunnel, thus you can't look in the west end and see one comming westbound until it clears the summit of the grade.
This tunnel is the primary limit on the number of trains they can run due to the amount of time between trains that it takes to clear the tunnel of exhaust gases. The UP upgraded the fans a few years ago, decreasing the amount of time it took to clear somewhat, but they are about maxed out on how fast they can get the exhaust out.