Mill Creek Central Trestle - Constructing the Deck
The towers and beams are up so the next step is to put a deck on the beams. Construction of the deck is described in this page.
Getting Started: We decided to make a small section of deck to see how we liked it before fabricating the parts for the entire deck. The key part of the deck is the Us made of 1.5" square tubing spaced every 5 feet. We cut enough tubes for 4 Us and gave them to Bruce Werner who welded the tubes, gussets and brackets all together. The photo at right shows the first two U's installed on the beams. We were happy with the basic design.
We initially planned to clamp the Us to the outside edge of the beam flanges. The clamps worked but we were concerned that vibrations might cause the clamps to rotate and come loose. We changed the plan to use pieces of 1.25" channel to clamp the U's to the inside of the beam flanges as shown on right.
We need to run 115 volt power and signal wires across the trestle so we decided to deal with that issue along with the deck. The photo shows a length of plastic conduit held in place by simple clamps we fabricated. The 115 volt power will be run inside the conduit. The signal wires are in a multiwire shielded cable that will be tied to the clamps. We'll be laying the conduit and tying down the signal cable as we install the deck.
The next step was to install the 5 ft long tie units between the Us. We made four tie units to go with the four Us. The final step was to drill and install the top rail angles. The completed 20 foot section of deck is shown at right and also in photo below.
The top rail angles were taken down to be painted along with the 14 additional angles needed for the rest of the railing.
Update 11-04-06: The photo at right shows the tubes for the last 28 Us. Each tube has three sets of holes drilled in it. The angle tabs stacked along the back also have one hole each. These pieces were taken to Bruce Werner's shop to be welded. Bruce is making the gussets that are also required in the assembly.
The channels along the left back of the photo are used to clamp the Us to the beams. The things with bolts sticking out the top are brackets that are clamped to the I beam flanges to retain the electrical conduit.
This photo shows the north end of the trestle on a very cold (~ 25 degrees ) sunny morning. The railings for the entire trestle have been painted and are on the deck.
The stack of steel rails will be used on the trestle deck. The first two rails have been laid on the deck to help align the track leading up to the trestle. Note that the track leading to the trestle uses aluminum rails.
We were able to work in the cold and managed to get the conduit and signal cable across the trestle before lunch.
This photo taken from the trestle deck shows the track across the meadow leading to the tunnel. The track was laid out so that the correct position of a grade crossing about 60 feet from the trestle could be established. The crossing will have steel rails embedded in concrete. We want to pour the concrete for this crossing and for the turntable before winter. (The turntable is just beyond the last visible part of the track. )
Photo below shows the entire trestle on this sunny morning.
Update 11-26-06: Bruce Werner has been turning out the Us at lightening speed. He has 25 done; only only seven more to go. The deck panel crew hasn't been moving as fast as Bruce.
The photo at right shows a 5 foot panel being assembled on the switch jig located in the steaming bay. A total of 31 panels are required, each with 14 ties and two side rails. The side rails are ripped from 2" X 10" X 10" treated boards. The ties are ripped from 2" X 10" X 8" and 2" X 6" X 16" treated boards. A total of 434 ties and 62 side rails are required. That's a lot of sawdust!
Dick is screwing a side rail to the ties in this photo. A total of 868 screws are required.
(Dick's shades may indicate a sunny November afternoon.)
The backhoe transports the panels to the trestle
We now have a little over half the deck installed as seen on the right. That is a flat car under the stack of steel rail. We're going to install all deck and then align it before laying any more rail. The photo shows that the north end (closest to the camera) needs to be moved an inch or so to the right.
This photo taken from the middle of the trestle shows the installed deck and the meadow to the north of the trestle. We took advantage of the nice weather after Thanksgiving to do final grading and layout several hundred feet of track. There is a grade crossing about 60 feet north of the end of the trestle which is ready for concrete that we hope to pour before the weather turns.
Photo below shows the entire trestle. If the weather holds Santa should be able to dive his sleigh across the entire trestle.
Update 12-8-2006: The Deck is finished! Photo at right taken from the south end shows the deck, the railing angles and cables. It was cold today --- mid 20s --- which motivated us to keep moving as we installed the cables.
The south end will be finished after the concrete pad is poured next spring. The rails can be installed as time and weather permits.
Photo below shows the view from the south west. Notice the traces of snow on the frozen ground. Brrrrrrrrrrrrr!