Western Railroad Discussion > Catching (Then Holding?) a Breath at the Top

The single track Tunnel 41 at the summit of Donner Pass is frequently a meet location between the limited number of westbound trains and the fleet of eastbound trains heading over the pass. I shared a video of the westbound ZG2LT a couple of weeks back putting on quite the show as the lead units of the train filled the tunnel with exhaust and the train's containers then spent the next five and a half minutes scavenging the tunnel of much of this exhaust.

On this same morning, an eastbound train, likely the MRVGR, was waiting for the westbound train to clear before it could proceed east. I've seen crews stop at East Norden in both directions to air up the train for the downhill run to Sparks or Roseville, but I'd be curious after a meet like this if they also wait for some of the exhaust to clear from Tunnel 41. Diesel exhaust, with PM2.5, NOx, CO, VOC combustion byproducts, etc., isn't the healthiest air to breath. Do modern locomotives have cab air filtration systems as part of the HVAC? Are eastbound trains on Donner permitted to hold for period of time after a westbound train passes through Tunnel 41 before proceeding, or isn't this really a thing?

Photos 1 and 2: Head and DPU power was seen at CP RV193 East Norden on Donner Pass on the morning of Sunday, July 5, 2026. UP 6004 was leading this eastbound train.
Video: You can see the amount of diesel exhaust still rolling out of the snow shed at the west portal of Tunnel 41 as the head end was entering.

Cheers,
Sean

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On tunnels of this length why are there not several exhaust fans?  Seems like that would mitigate the problem

Historically this tunnel had been for eastbound trains, with westbound trains taking the original route over the pass via Main 1. That track was pulled in the mid 90s, requiring westbound trains to fight the grade through the nearly two mile long tunnel. I don't know why forced ventilation was never added to this tunnel at either East Norden, the high point, or Eder, at the east end.

Nice video!

texchief1

Sean, don't want to hijack your nice video, but here is one of mine from pretty much the same location many years
earlier with UP unit with horrid Nathan P3 horn, probably from an old SP unit.
Regards, Jim Evans

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NIce shots!

No clue why they don't ventilate the Big Hole.  I've ridden the Zephyr a few times and I remember that they asked passengers to not move between cars while in the Moffat Tunnel, and you could really smell the exhaust as we rolled through.  But I don't recall a similar request for the tunnel over Donner.  Had hoped my rides over Donner when I was a freshman in college would take the original route through the snowsheds, but no such luck.  :(

Nathan

Did anyone else notice in  the earlier video posted by five chime there is no graffiti ? There may have been one car tagged. Your lucky now if one car on a long train is not tagged. How did it get so bad so quickly?

Jim's video is likely from sometime in the mid 2000s. (UP 6841 looks like it had a build date of 10/95. UP 6432 was built 10/00. UP 5563(?) or 5565(?) was built 7/04.)

20 years is not even a blink on a geological timescale, but 4/10 of a lifetime for me. I blame the graffiti on the spray paint lobby and dirty politics.

clickclack Wrote:
-------------------------------------------------------
> Did anyone else notice in  the earlier video
> posted by five chime there is no graffiti ? There
> may have been one car tagged. Your lucky now if
> one car on a long train is not tagged. How did it
> get so bad so quickly?