On CN in B.C, the trestle was originally built as part of Canadian Northern’s main line to Vancouver. Today it on the CN Clearwater Sub, which sees well over 20 freight trains each day.
As the story goes, a large fill on the line north out of Utica is the product of a trestle built there. According to the story, a state bridge inspector looked the structure over and noted that it probably wouldn’t last very long.
The railroad was unconcerned, as the only reason the trestle was built was to get to a source of fill on the north end. Apparently the top of a hill was removed and dumped over the trestle.
The line is still in use, and I’d imagine that if the fill was ever removed, the remains of the trestle would still be evident.
The Central Pacific filled in many of their trestles in a relatively short period after the line was built. Main reason for the trestle was that it was faster to put in a trestle than a fill. Having the trestle made it easier to construct the fill as the earth was simply dumped from cars on the trestle.
There’s a fill on the Carson & Colorado grade just below the tunnel on Montgomery pass that looks like a filled in trestle. The angle of repose of the fill looks a bit steep for an ordinary fill.
Thank You for posting the film on the embankment construction!
There were still a few steam shovels in use just after the War used in construction and they were a treat for a child to watch. Also, the occasional appearance of a Steam Roller and trucks, Chain Drive.
Bread and milk were delivered by wagons pulled by horse, coal, wood and ice arrived in trucks.
Great action shots of the Steam Shovel and it’s Construction trains.
We saw a Lidgerwood at work, pulling it’s plow thru a string of Gondolas, possibly the last use of such equipment in our area. All went for scrap in '62 after years of storage.
Anyway.
There is a similar Steam Shovel in New York State, as here.
About 55 years ago I read about a Vulcan Rail Steam Shovel abandoned way up in the mountains at a gold mining claim, it being used to remove overburden to get at the gold in the creek below.
I’ve seen steam powered cranes and pile drivers on Manhattan construction sites in the early 1970s. In the early 1990s I saw a steam powered dredge in the Hudson river near Poughkeepsie. I would have loved to go on board but it was anchored in the middle of the river.
Not far from me (5 minutes) is a fill of an old iron bridge (actually the 2nd bridge at that site) of the Catasauqua & Fogelsville Railroad, but they used iron furnace slag instead of earth or rock.
The construction of the 3rd bridge in 1917, showing some of the filling of the 2nd bridge in progress to the left (track in the foreground is the Allentown & Slatington Electric Railroad - note the 3 poles on the left for the trolley wire);
Building a trestle and then filling it in is probably more common than one thinks. the large fills on the western edge of Omaha on the UP’s Lane Cut-off were built that way. There’s a picture of one being filled in hanging in a UP building in Council Bluffs. I’ve seen it on the internet, too.
On the Boone and Scenic Valley’s line there are 8 locations between their high bridge and their Des Moines Rivwr bridge that had trestles that were filled in over time. The FDDM&S interurban filled them in using cinders from their on-line generating plant. Some years back, they were doing some maintenance work at the bottom of one of these fills and unearthed part of the wooden structure.
The centre casting of the table was hollow, by Teddy’s left knee, and bushed with a bronze bearing to allow chain and table to revolve on centre as boom swung.
Boom swung by a cable with it’s own steam engine and drum.
The man on the Boom racks the Dipper in and out against the bank using a two cylinder steam engine which exhausts at the top of the boom, he opens the bucket door latch w a lanyard.
Note flexible steam pipe couplings above pulley.
Steam Shovel Engineer and controls, Throttle top left.
Many Trestles were constructed with the INTENTION of filling them in at a later time.
In this way untreated timber, often cut locally in mountainous country, was used, saving the costs of treatment and shipping.
One of the locomotives that was owned by the contractor is now preserved at the B.C. Forest Discovery Centre. Due to his small fleet it most likely worked on the Lyon Creek job.
The centre casting of the table was hollow, by Teddy’s left knee, and bushed with a bronze bearing to allow chain and table to revolve on centre as boom swung.
Boom swung by a cable with it’s own steam engine and drum.
The man on the Boom racks the Dipper in and out against the bank using a two cylinder steam engine which exhausts at the top of the boom, he opens the bucket door latch w a lanyard.
Note flexible steam pipe couplings above pulley.
Steam Shovel Engineer and controls, Throttle top left.
Many Trestles were constructed with the INTENTION of filling them in at a later time.
In this way untreated timber, often cut locally in mountainous country, was used, saving the costs of treatment and shipping.
Thank you for using the phrase “angle of repose”. I took geology as my lab science in college (figured a farm boy couldn’t go wrong with rocks and dirt), and finally (42 years after graduating) was able to use something I learned in my lab science class to understand what someone was trying to communicate.
Question. Since filling in a bridge does not allow for compacting the fill is there a requirement for later much more surfacing of the fill area to keep track useable ?
As long as the original timbers are still supporting the track, no extra track surface work is needed until the timber rots away. Most likely, most of the timber will stay as-is as there isn’t as much oxygen to promote decomposition. Worst case, the top foot or two is all that decomposes.
Some believe, incorrectly, dropping the soil or other material from a great height will compact sufficiently upon impact.
The lower layers of the fill will be gradually compacted by the weight of all the fill above them. Obviously, that effect diminishes the closer the fill gets to the track. Once the track is being carried by the fill, it will be a few years to a few decades until the settlement decreases to no longer require more attention than the adjoining track.
Early in my career an assignment was to monitor the superelevation in an industrial park lead curve on a fill that was only about 10 feet high, and only about 5 - 6 years old. For as long as I had that position - a little less than 2 years - every couple months it would settle so much that the curve had ‘negative elevation’ = the outer rail of the curve was up to 1" below the inner rail, not a good condition and a possible defect, depending on whose criteria was being applied. So a crew would spend about a day adding ballast and then raising and tamping that section. The owner spent some money on a geotechnical investigation to see if that condition was being caused by a sinkhole (no, it wasn’t), and may have tried lime or cement stabilization, but that didn’t solve the problem either. My thought at the time was that the compaction specifications for the fill were either not very high or weren’t followed, but I never saw those specifications or any tests to confirm or refute my suspicion. In general I think compaction specifications are not as stringent as they could or should be - which with modern equipment can be achieved within reason - but that is a topic for a different forum.
I have a vague recollection about RR fills typically taking 5 or so years to fully settle under traffic. Along those lines, Trains had published a picture of an NP articulated locomotive that derailed while being used to speed the settlement of a recent fill.
On a related note, my cousin’s husband had worked for the Montana Highway Department for a number of years and one pf his early jobs was taking soil samples for compaction testing. That left a niggling question in my head as to what was involved - eventually bought a book on geotechnical engineering to satisfy my curiosity.
Not only does soil compaction require force, but it also depends on soil type and moisture content. Too much moisture creates a film around every particle which prevents them from achieving an interlocked effect in the compaction. When this overly wet soil is compressed for compaction, it is like dough. You push down here and it rises up there.
Too little moisture fails to produce the thin film of water that lubricates the particles to help them slide together. Looking at the soil being loaded in the video suggests that it is too dry for optimum compaction.
Water could be added to the soil by wetting down each load dumped. Also, breaking up and saturating soil with high pressure water hoses is another form of soil consolidation called “jetting.” This at least breaks down soil chunks to eliminate any large voids in the fill, but it leaves the soil too saturated for proper compaction.
Proper soil compaction with compacting equipment must be done in layers called “lifts.” These are horizontal layers of fill laid down in a controlled loose thickness such as 8 inches. I am guessing that such pe
There was a feature in one of the railroad magazines back in the Fifties, where the Northern Pacific?? sent a large Articulated locomotive light engine to a newly-completed branch line under direction of a Roadmaster to run back and forth over a new fill to tamp it down.