As far as I can tell in my research, most tunnels over a quarter-mile long were built with vertical ventilation shafts. When building a long tunnel the first thing that was done by the surveyors and engineers was to remove all of the trees and foliage up the side of the mountain/hill on a line exactly over the intended line of the tunnel and down the other side. This gave those guys a clear look “over the top” with their instruments (trig?) so they could start digging from both ends simultaneously and have everything line up. Sometimes they ran a telegraph wire over the top so they could communicate with the crew on the other side. At the same time they were able to use trig to drop vent shafts from the top that would meet up with the tunnel when the diggers got to that pre-determined distance. So most tunnels had three or more crews working simultaneously. In the “old days” they also worked around the clock.
…Bucyrus: Yes, hadn’t thought of the fact you mention of less oxygen available for the engines in the long tunnel…and with the fuel delivery set…Guess the result would be excessive smoke.
And yes, I agree, the last engine was one with very bad smoking condition…Again, I wonder how it continues to run. The prime mover certainly needs oxygen to make combustion.
Isn’t that why they built “tunnel motors”? I’m not an expert, but to me it appears none of the four units in the video is a tunnel motor.
…Can add just a bit to P Z’s mention of cutting ROW up and over when building tunnels.
Building the original 160 miles of Pennsylvania Turnpike required to create {and or finish}, a total of 7 tunnels.
I remember they did cut a ROW {clear cut}, up and over to open a path along the exact route of the tunnel below.
But in building the tunnels for that project I am reasonably sure there are no vertical shafts for ventilation. Of course these would be highway tunnels…{not originally intended to be though}. Back in the late 1880’s they were intended to be RR tunnels.
Each tunnel has a vast ventilating {powered large fans}, system in place to remove unwanted exhaust as necessary. Believe there was one that required just a powered vent system at one end as it was the shortest of the seven tunnels. There is space above the ceiling of the tunnels to carry the venting flows, etc…with vents at appropriate locations along it’s length.
…P Z: Doesn’t the “Tunnel Motors” have to do with modifications to the unit’s cooling systems…?
Modelcar, when I was in PA I remember hearing that the tunnels in use today are not all on the sites of the original tunnels, as the turnpike has been realigned a few times. How many present tunnels are on the original seven sites?
Could be. But the only major difference I was aware of – again, I’m not a locomotive expert – was that the air intakes were located lower on tunnel motors, down near the walkway to have a chance of sucking in air instead of exhaust.
…Laurel Hill, Ray’s Hill and Sideling Hill tunnels were bypassed some years ago.
Originally there were 7 tunnels on the original 160 miles of Turnpike that opened in Oct. 1940.
The remaining 4 still in use, have had a parallel tunnel bored next to them to provide 4-complete lanes…2 each way. {So these are on original sites}.
Yes, some of the turnpike has been rerouted…Example: Near Breezewood and east…About 13 miles…Believe this change eliminated the Rays Hill and Sideling Hill tunnels. Another area is east of Allegheny tunnel…{not effecting the tunnel}, and on down towards New Baltimore.
Laurel Hill {west of Somerset}, was bypassed by a mammoth cut but still maintained the max grade @ 3%…Same with all the by passed tunnels. No grade steeper now {since relocations}, then on original area of Turnpike than 3%.
Recent changes also includes massive work adding another lane on up grades for slow moving vehicles, etc…
Edit: P Z…In rereading your question about some tunnels not on original locations…Got to thinking, maybe you mean…compared to original RR tunnels. If that’s true, the Allegheny tunnel used for the turnpike was moved about 85’ south of original RR bore as that bore had some unstable rock inside and the engineers decided to move as stated above to a better rock strata, etc…
Another item: Laurel Hill tunnel {east}, entrance {for the RR was to be about 1000’ farther east than where the Turnpike locaters started with their east entrance, but did go in on original bore.
Those are radiator air intakes, the engine air intake is the grille near the top of the long hood right behind the cab, and it is in the same location on the tunnel motor as it is on a regular version.
1). So then you actually agree that Piston effect is one method employed for tunnel ventilation? we agree then
2). Hey , it was you trying to insist that Chimneys function only because the air moving horizontally across the stack, I was just lampooning the fact that chimneys are more versatile than you were admitting to.
Hot air rises, but then you obviously are aware of that.
…Haven’t had too much comment of what the tunnel entrance doors purpose are…
As I wrote earlier in this thread, I thought tunnel doors purpose {at least in some cases}, is to keep the tunnel air “in place” while a train works it’s way thru so the radiators of the engines can have “new” air as it moves forward and not the heated air surrounding the engine if it would be allowed to be “pushed ahead” as the train moves forward.
Any thoughts…
That is right Quentin. This also caused pressure to build up in front of the train, and the engineer’s ears would pop in some tunnels when the door went up.
Jack Wheelilhan wrote an interesting article in the 2-00 CTC Board magazine. He was helping with the delivery of GN’s first GP30s in 1963. When the Cascade Tunnel doors went up, all four GP30s shut down because of the Paxton-Mitchell Crankcase Pressure Detection Device.
…Thanks Dale…That’s pretty wild. The engines shutting down.
A little humor!!!
Several years ago I was in Colo. Springs on busines and as I did when I had time late in the day I called an old friend who was a partner in a major garage door business. This firm installed more that garage doors; ranch and farm gates were a specialty.
As my friend and myself sometimes exchanged practical jokes I decided on the spur of the moment to try another. Disguising my voice I called and got the receptionist, (who knew me). I gave a fictious name as an engineering official with the D & RGW and advised that I was waiting on another call but would like to know if their firm had the ability to install doors on the Moffet Tunnel that could be operated by train crews with an electronic opener that each lead engine would have. I knew this was my friends specialty but proceeded by telling the receptionist, who did not recognize my voice, I was in C. Springs and would come to their plant and offices later in the day if they were interested. Of course they were interested and the lady told me to come by as they would stay open to see me.
I entered the office about five minutes before their usual closing time and announced my D & RGW name to the receptionist who broke into laughter and after controlling her emotions called my friend to announce that the man from the Rio Grande was here. My friend and his partner came into the reception room and proceeded to provide me with a few names that shall not be presented here. Then they broke out the cocktail glasses and advised that I had one coming for this prank; and of course they got back at me later.
[(-D]
I love good practical jokes.