Chapter Notes: Cascade Tunnel (Destination Unknown) · 2:27am Jan 21st, 2022
Westward! Sweetsong’s found a good car to ride, one that’s safe and secure. There’s only one little flaw in her plan; maybe she should have looked at that map in the station more carefully.
Special thanks to AlwaysDressesInStyle for pre-reading!
Railroad signals are complicated, and this is hardly the place to take a deep dive. The very, very simple primer (in the US) is a green signal or a clear signal (they weren’t always green and in some places still aren’t) means you can proceed at full authorized track speed. A yellow signal typically means ‘slow, prepare to stop at next signal,’ and a red signal means stop.
In actual practice, though. . .
Source
(This is just one railroad with a unified system, so it doesn’t have any position-light signals, which some Eastern US railroads. You will notice, for example, that a red signal could mean ‘stop and proceed’ or ‘stop’.)
Anyway, while Sweetsong might have faith that the signals always work as intended and the crew always obey them, there are plenty of real-life examples I could cite of trains running through signals they should have stopped for, even automated and generally highly-reliable systems ‘losing’ a train and then another one runs into it. In-cab signal repeaters, positive train control, and various different warning systems help, but they’re not foolproof. Even derailers (which do what it sounds like they do) after high-consequence signals don’t always work; if the train’s going fast enough it’ll still slide far enough to yeet itself into the river, as New Jersey Transit found out back in the 40s.
Not to mention there’s always the possibility of mechanical failure—rare but it does happen. Even when the signal aspects are correct and the crew tries to apply the brakes, if the brakes don’t work. . .
To Sweetsong’s misfortune, Cascade Tunnel is the longest rail tunnel in the US. The original was built by the Great Northern in 1900, and during a realignment (to eliminate switchbacks and challenging winter weather), they completed the new tunnel in 1929. It is nearly eight miles (12.5km) long.
One of the problems with tunnels is how you get rid of the locomotive exhaust. While the tunnel was originally meant to be used with electric locomotives, it was later converted to use with diesels by means of a ventilation system.
While you might imagine such a system to consist of numerous bore holes to the surface, perhaps with fans on them, that’s not what the Great Northern did. Instead, the eastern end of the tunnel has a giant door which closes and a pair of huge fans blow air into the tunnel. There’s a half hour dwell time after a train has passed before it’s safe to send another one through, and just in case something goes wrong, the crews of trains going through the tunnel have portable breathing apparatus, and there are various emergency stations inside the tunnel that have more breathing equipment (and other supplies).
Not the place to be riding inside a train.
Also, for what it’s worth, Amtrak goes through that tunnel and at least when I rode it, they didn’t provide the passengers with emergency equipment.
Here’s what it looks like from the back window of an Amtrak train:
[If you just want to see the tunnel part, skip to 18:43]
Trains go through the tunnel at reduced speed; according to one source it’s 25mph (40 km/h). It’s also a huge bottleneck for the BNSF, but of course it’s very expensive to build a new tunnel, so they deal with what they’ve got. Eastbound trains have to wait for the tunnel to clear, but westbound trains don’t, since the exhaust of the previous train will stay in front of them, and apparently then an eastbound train can go in because the westbound train brings its exhaust with it. (According to this tunnel forum)
In short, this is not a place for a pegasus.
One of the challenges for trains in general is that they’re really efficient when it’s flat and level, and when it’s not . . . well, trains don’t like that. Even fairly reasonable gradients (by car standards) are a huge hurdle for trains, and that’s not even factoring in the additional friction caused by going around curves or the train handling challenges of rolling terrain, where some of the train is going up a hill and some of it is going down a hill.
I think I mentioned in a previous blog post that most of the UP’s really big locomotives (the Big Boys, the Centuries, etc.) were meant to get trains over the Wasatch Mountains. If you haven’t got one big locomotive, you can double the train (where you split it apart, run half up the mountain, leave it there, then bring the second half up) or use helper locomotives pushing or pulling.
And once you’re at the top, you’ve got the added challenge of coming back down. You don’t have enough horsepower to get up, the train stalls on the grade and you call the dispatcher to send more locomotives to help push. On the downhill side, if you don’t have enough braking power . . . there aren’t runaway train ramps.
One of the most infamous such disasters in the US was the Cajon Pass runaway, or the San Bernardino train disaster. The load was miscalculated, and the train did not have enough braking power to stop or slow itself on the grade. Maybe in another blog post I’ll talk about dynamic brakes, since they were a factor. The NTSB later determined that once the train got over 15mph (24km/h) it could not stop on the downgrade; the authorized speed was 25-30 (40-48km/h)mph.
The engineer quickly realized that he could not control his train, but by then it was too late. Brakes fully applied, the train accelerated to an estimated speed of 110mph (177km/h) and came off the rails at the first curve.
Now for a song that’s going to be familiar to many. Not only does it have a train, but it also has some valuable life lessons, and not just for gamblers.
Kenny Rogers passed away in March 2020. He truly knew when to fold ‘em.
I'm a locomotive engineer. I run on part of the NEC (Northeast Corridor).
I'm enjoying reading about these parts of the railroad.
Red pony in the first picture:
"Looks like the middle thingamabob is comin' loose from the doohicky. Needs fixin' real soon."
8 miles in 1900? Was suprised there wasnt ventilation for steam given the cost of electrification?
5629690
He sure did.
I saw him in concert years and years ago . . . back in the 90s. . . .
5629714
Cool! Can I pester you with train questions if I have them?
I'm enjoying reading about these parts of the railroad.
Thank you!
5629766
Those are technical terms spoken by a pony who knows about these things. You can tell just by looking at her.
5629909
I think that they couldn’t figure out how to ventilate the tunnel, although I don’t know for sure. One source says that only the tunnel was electrified (and I suppose a small yard on either side of it, where they’d take the steam locomotives off the train and hook on the electrics).
If memory serves, they did the same in the original Bluewater Tunnel, which ran under the St. Mary’s river between Sarnia ON and Port Huron, MI. There was no way to practically ventilate a tunnel under an active shipping channel, so they used electric locomotives to pull the trains through.
5630024
Sure. I run electric passenger trains so if they are freight or diesel specific, I might not know.
5630028
Regardless of her/his/whatever professional achievements, consider replacing the Russia-related picture with more patriotic one before some thingamabob from the blue party office with too much free time complains about it.
You're interesting read, it will be a pity to lose you just like that.
Thanks for writing, chapter and blog post both!
Here is some more footage of trains entering and exiting the tunnel. (You can see the ventilation system coming online at 10:08 and again at 14:05)
Are there any videos or pictures of that available online? That sounds rather interesting
More rail songs? More rail songs!
(Dave Goulder - Eight Freight Blues)
Something a little more... metally Trains do not have to be exclusively folk and blues.
(U.D.O. - Trainride in Russia
Now I'm imagining the Great Amtrak Asphyxiation Disaster of 2023.
5630070
Cool!
Also, if you haven’t seen it, you might want to check out JZ1’s story on the NEC:
- MLP: FiM
- Adventure
- Comedy
- Slice of Life
During a diplomatic mission to Earth, Princess Celestia goes out in search of pizza and adventure.It’s a good one
5630146
You’ve missed the stories where I made fun of specific politicians, haven’t you? If they were going to get me for something, it wouldn't be a picture on a blog.
And honestly, going back to jail for a ponyfic would actually be hilarious.
5630481
You’re welcome!
5630513
I was actually gonna post that YT video, too
None that I’ve found, but I didn’t look that hard. I’d imagine just small, well-marked rooms, based on what other tunnels do.
Excellent songs! I really like the second one!
5632122
That’s a disaster Amtrak hasn’t had yet.
5632526
:)
5632122
5632530
Well, I don't know what emergency plans they might actually have, or the exact profile of the tunnel, or the like, but since as far as I know it has a monotonic slope, one potential option seems to me to be just shutting down the engines, releasing the brakes, and letting the train roll out. Checking Wikipedia, it looks like the eastern end of the tunnel is the higher end, too, so it wouldn't be a problem even if the doors were stuck shut.
5632566
You got me curious, so I started digging. I found a link to BNSF’s operating instructions for the Scenic Subdivision, which is where the Cascade Tunnel is located. There are 21 bays in the tunnel which contain a phone and SCBA replacement cylinders; crews are issued SCBA equipment at Balmer yard or Wenatchee.
Here’s a link to the PDF; the Cascade Tunnel operating rules are 62-64
5632729
Oh, neat; thanks. :)
5630030
From what I recall from The White Cascade(a very interesting book on one of the main reasons for the new Cascade tunnel and the worst rail disaster in North America), the electric locomotive simply hooked onto the front and the steam simply put their fire out before entering.