Thursday, January 10, 2008

...About That Bridge

A couple years ago--pretty early in my blogging career, actually--I put up this post about my favorite element of our local infrastructure, an old railroad swing bridge not far from my house. As I've mentioned in other posts, the extensive system of locks and dams found on our local Fox River are being rehabilitated after a couple decades of neglect and inactivity. The non-working condition of almost all of the 17 locks have made boat travel along most of the 30-mile length of the Lower Fox River impossible. Though this inactivity stretches back for the entirety of my presence here in Appleton and beyond, it surely has changed the character of the river and its presence through the cities located along its length. Reworking them is a gigantic undertaking, and is bound to impact the flavor of life in Appleton.

(An overview of lock and bridge. To the left, just out of the frame is a
dismantled,lifting auto bridge which is being rebuilt. The construction
trailers partly obscuring thelock are for that project.)

That, plus my just generally being a slave to mechanical and infrastructure-related things, has made the details of the river's rehabilitation freakishly fascinating to me. It's mostly about the locks, of course, and I can obsess over those quite easily (they're an oddity, something peculiar to rivers, and they have a crude, mechanical magic about them--like an unpowered elevator for any size boat that can fit in them); but this one railroad bridge just set its hooks deeply in me at our first acquaintance, and it hasn't let go of me since. The bridge hasn't swung in over a quarter century, and since I knew that rehabilitating the river for boat traffic would require doing something with this bridge--it's so low to the water that not even a canoe could get under it in the closed position--I've been waiting with bated breath for the crews to begin work. Would they tear it down and put up a new one in its place (and if so, would the new one be of the same kind)? Would they just give it the lipstick and rouge treatment? Or would they just force it open and stop using the tracks altogether?

(From the shore, the navigation channel leading out of the lock to the bridge.)

This last question was a poignant possibility, I feared. The Fox River Valley is littered with now-unused railroad tracks and abandoned river bridges, and the paper industry which put this area on the map is a shadow of its former self. But this particular crossing remains in daily use, and it's noteworthy both for its proximity to, and symbiotic working relationship with Appleton Lock #3 just a stone's throw upstream, and also for the quite steep grade which the loaded trains must pull up immediately after crossing the swing bridge. From my kitchen I can see and hear the trains pull up or coast down the hill by the bridge every day (one is straining uphill across the river as I write this).

Out for my walk over the last couple months, I've seen crews finally starting to work on the bridge. So far they've busied themselves with replacing the roadbed itself, putting new ties under the rails, and the walkways on both sides of the track. But in the last month there seems to have been a flurry of further activity which I've missed because my absences during the busy holiday work season. Today as Susan and I walked past there was a crew working on the near side of the bridge, so I stopped briefly for a chat. Turns out, this guy (and the two others who joined him) had all the dirt--as I guess you'd expect from employees of Canadian National tasked with getting the bridge working again.

(The approach from uphill. To the left thru the trees are the downstream
gates for Appleton Lock #3.)

To my delight, the plan is for the bridge to resume normal swing operations, and it is being restored accordingly. The alternative would be to route the daily traffic considerably out of the way, and, as he told me, "This route is a good money-maker for the road." I learned that the bridge was put up in 1926 and that it has an exact twin from the same time and manufacturer in Green Bay.

(The crumbling downstream support trellis for the open-position bridge.
Work will begin on these shortly.)

He said that shortly before the bridge ceased swing operations in the early '80s the then-operator actually jacked the whole bridge up and rehabilitated the huge, central bearing on which the bridge pivots. So that crucial component--one of my big questions earlier--is thought to be fine. But the rest of the mechanism is being rethought and reworked. The whole swinging business used to be accomplished from a booth suspended above the center of the bridge by an operator, with motive power supplied by an old flat-head six cylinder car engine. With a series of huge, crude pedals and levers, the car engine and operator did everything in a choreographed routine: pull out steel wedges beneath both ends of the bridge (used to give a solid surface for the rolling trains); rotate cams to raise the rails at both ends of the bridge from their locks; and slowly rotate the many-ton steel trellis about 45° counter-clockwise by way of a shaft which runs from the operator's booth down to a ring and pinion in the center below the tracks. When the boats had passed, do the same thing in reverse.

The rehabilitated bridge will follow the same basic choreography, but it will be accomplished with a series of new electric motors spliced at key places into the old mechanism. Bridge activation will be accomplished not from the operator's booth on site, but from a dispatcher's desk some 60 miles away in Stevens Point. Surveillance cameras have been installed, providing the remote operator with a view. Another interesting tidbit is that the bridge will be left open now so that boats may pass, and it will be momentarily closed for the passing of trains and then opened again. This gives boats unfettered access to the river except when a train is passing. One practical consideration with this is that trains must now be restricted from beginning the steep downhill run by a remotely-operated signal until the bridge is confirmed closed and locked; if a train should have a brake problem coming down the hill, it would end up in the drink if the bridge were open! I hadn't thought of this.

(The new lift-to-unlock rail sections on new tie beds. The steel grid walkway is
part of the swinging section of the bridge; the nearer solid tiework is stationary.)

(The 80-year-old cams which lift the rail ends to unlock them for swinging.)

(A new electric motor grafted onto the old shaft and cog mechanism.
This shaft used to continue on up to the operator's hut in the bridge center.)

(The same mechanism that raises the rails also, through these gears,
pulls the wedges beneath the road bed.)

(The old operator's hut. Look closely and you'll see the new cameras.)

(New conduit and electrical machinery next to old iron stairway up to operator's hut.)

(Everything used to be operable in a pinch by cranking on this huge nut in the
middle of the roadway at the bridge's center. Hey, good luck with that.)

(The upstream support trellis and the exit to Lock #3.)

I honestly don't know why, but it absolutely makes my day to see this bridge getting attention. The idea that it will continue to function--no, that it will be resurrected to function as it used to--gives me a silly glow.

He said that they expect to begin practice swings in the next few weeks. The open-position support trellis needs to get rebuilt, and the actual swinging motor is waiting in a warehouse in Fond du Lac.

I hope I'm there to see it.

(I'm on vacation for a few days. In case anyone wondered why things are so quiet.)


Jeffy said...

Very nice story about the bridge rehab. I too love to see this kind of thing happening.

I am amazed that you could get so close for so many photos while the project is ongoing.

I'll have to get some pics of the bridge project going on next to my office and put a post together. It is entirely different, but also quite interesting to watch.

wunelle said...

I was able to get so close because no one was there. Plus, its designed to walk all over, even if they dont want ME there!

I think I could sit and look at the old mechanisms for hours.

Id love to see what your bridge reconstruction looks like! (apparently, Mexican typists dont use their apostrophe much, as it seems hard to get at. Ergo, no punctuation!)