Talk:Cascade Tunnel

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[edit] Gradients

What is the gradient of the second Cascade tunnel, and which end (E or W) is higher in elevation?

Tabletop 07:54, 7 October 2005 (UTC)

The gradient in the tunnel is 1.7% and the higher elevation is at the eastern end.

After reviewing more articles the gradient appears to be closer to 1.6% so I've corrected it. Also close inspection of pictures of the west portal gives the length as 41152 ft. and the elevation as 2247ft. and pictures of the east portal gives the length as 41183 ft. and the elevation as 2881 ft. The difference in length is due to adding to the tunnel for the doors at the east end. The length on the west portal is the original length without the doors. The difference in elevation of 634 ft. divided by the original length of 41152 ft times 100 for percentage gives 1.54% for the gradient. However the gradient is slightly higher since the gradient transitions to level as the track exits the east portal before starting down hill at a 2.2% gradient. —Preceding unsigned comment added by 24.19.45.169 (talk) 23:17, 31 October 2007 (UTC)

More research turn up the precise number as 1.565%. 24.19.45.169 (talk) 02:02, 26 January 2008 (UTC)

[edit] Switchbacks

It looks like the old tunnel didn't avoid all switchbacks, and that there was one at Scenic and one north of Deception Falls. Is this correct? --SPUI (talk) 20:13, 24 November 2005 (UTC)

Never mind - I found a map that shows a sharp hairpin curve at each end. The one north of Deception Falls was in a tunnel. --SPUI (talk) 23:26, 24 November 2005 (UTC)

[edit] "longest tunnel" claim

the article states "It is the longest tunnel in the United States." i think it was the longest tunnel when originally constructed, but is it still? there are longer tunnels that are not rail tunnels - there's a 100+ mile tunnel providing water to NYC, for instance, but i'm not sure if there are longer rail tunnels or road tunnels in the US. —The preceding unsigned comment was added by 66.92.68.224 (talk • contribs) .

I believe the intention was that it is the longest railroad tunnel in the United States. I fixed the article to state longest railroad tunnel.

[edit] Ventilation system (under History)

Can someone familiar with the subject clarify the ventilation system? At present, it refers to trains entering the EASTERN portal, which means trains going downhill. Why would they need any ventilation at all? And why does closing doors and turning on fans at the same time help? - I would have thought closing doors would defeat the purpose of the fans. --Ian Page 23:06, 19 July 2006 (UTC)

"In addition there are stations spaced every 1500 and 2500 (based on location in tunnel) that provide additional air tanks and equipment to be used in the event of a failure."

What measurement is being used here? Murderbike 07:37, 22 May 2007 (UTC)

I believe the measurement is feet. However, I could not find any reference to verify it. The fans and doors go together and are at the east end of the tunnel. Turning on the fans without closing the doors will allow the air to blow out the east end without ventilating the tunnel. The tunnel is basically 8 miles long and a 100 car freight train is around a mile long or 1/8 of the tunnel. A train travels at 20-25 mph through the tunnel taking around 20 minutes to traverse the tunnel. A train in the tunnel is like a piston in a cylinder. It pushes the air in the tunnel out ahead of it. This leaves the hot exhaust gases in the tunnel causing the engines on the next train through the tunnel to overheat. Even a westbound (downhill) train will have the engines idling. Blowing both fans behind a westbound train will clear the tunnel of exhaust gases as the train exits the tunnel allowing the next train to immediately enter. For more detailed information see http://www.halcyon.com/tawhite/CASCADE%20TUNNEL.html —Preceding unsigned comment added by 24.19.45.169 (talk) 20:18, 1 November 2007 (UTC)

[edit] Separated Material on the Cascade Tunnel from Material on the New Cascade Tunnel

I separated the material on the original Cascade Tunnel from the material on the second Cascade Tunnel to make it easier to add material and perhaps at some point create separate articles. —Preceding unsigned comment added by 24.19.45.169 (talk) 23:15, 1 November 2007 (UTC)