Saturday, December 20, 2025

1964 Chatham and Division Street Bridges over CalSag Channel in Blue Island, IL

Chatham: (Archived Bridge Hunter; Bridge Hunter has been hacked?; Historic Bridges; Satellite)
Division: (Archived Bridge Hunter; Bridge Hunter has been hacked?; Historic BridgesSatellite)

I wonder how far away those smokestack were. Today's CalSag is wider than the original one.
MWRD posted
A view to the south showing a bridge over the Cal-Sag Channel at Chicago Street in Blue Island, Illinois, on August 29, 1924.

Chatham Street Bridge with a little of Division Street Bridge in the left background.
Street View, Jun 2023

One of a pair of nearly identical bridges over the Cal Sag Channel in Blue Island. The other is at Division Street, and was in about the same bad condition prior to their rehab.
Rehabilitation of this bridge for pedestrian and bicycle use as part of the Cal-Sag Trail is complete. It also serves pedestrian traffic from the south side of the Cal-Sag to the Metra commuter train stations on the north side of the Cal-Sag.
It needed repairs badly - It was closed to traffic but left open to pedestrians after the 2010 inspection rated it "Imminent Failure", but then in 2015 it was also closed to pedestrians. It appears that between 1964 when it was built, and 2016 when rehabilitation started, it had received no maintenance at all, not even painting.
The 2016 rehabilitation replaced and narrowed the deck, and rehabbed the steel superstructure. The narrower deck has exposed the bottom chord and its complex connections to easy view. This is not always possible on steel truss bridges, making this a very accessible bridge for one wanting to study what holds steel truss bridges together.
[BridgeHunter_Chatham]
Before the 2017 rehab
Street View, Jul 2012

Both bridges were built in 1965, neglected, closed in 2010 and rehabilitated in 2016. However, Chatham Street Bridge is not for non-motorized traffic only.

"This bridge is one of two nearly identical bridges in Blue Island that are both deteriorated and closed to traffic. The reason for the deterioration appears to be caused by a nearly complete lack of maintenance, repair, and rehabilitation over the bridge's relatively short service life. From a historical perspective, the lack of maintenance is interesting since aside from the deterioration, the bridge appears as it was when first built. The original concrete deck remains, with only some minor patching for potholes. Original pedestrian railings remain, and typical of older truss bridges with sidewalks there are no railings between the truss lines and the vehicular roadway. Original stringer approach spans remain in place. Expansion joints also appear to be original. A bridge painted date is painted on the bridge as May 1965 which indicates the bridge has never been repainted since its initial painted. There also is no evidence of spot painting. It is this lack of even basic spot painting over the bridge's service life that most likely has led to the isolated areas of complete section loss on a number of vertical members. This bridge is thus an excellent unaltered example of a 1960s truss bridge as much as it is an excellent example of the value of basic maintenance such as spot painting, which would have been drastically cheaper than a rehabilitation would be, or even worse, a complete structure replacement." [HistoricBridges_Chatham]

This view shows how we can see the under deck girders and their attachment to the trusses. I have to give some thought to making a road trip.
Street View, Apr 2025

Division Street has a more traditional portal view of a truss bridge.
Street View, Apr 2025

CB&Q Four Mile Bridges over Des Moines River between Ottumwa and Chillicothe, IA

1903: (Archived Bridge Hunter; Bridge Hunter is broke, no Historic Bridges)
2002: (Archived Bridge Hunter; Bridge Hunter is broke, no Historic Bridges; Satellite)


Joy Taylor posted
The BNSF Four Mile Bridge spans the Des Moines River near Ottumwa and Chillicothe in SE Iowa.

JohnMarvigBridges, cropped
Located between Ottumwa and Chillicothe, this massive bridge is locally known as the "Four Mile" bridge.
The original bridge here dates to the 1860s. However, that bridge was upgraded at least once before this bridge was built. In 1903, the CB&Q double tracked this bridge, building a five span pin connected Pratt Through Truss bridge, approached by seven spans of deck girder on the west, and five spans of deck girder on the east.
This iteration of the Four Mile Bridge was one of several spans built by King Bridge Company for this line. Several others, although much smaller spans, were also built during double tracking projects.
In 2002, BNSF decided to upgrade the bridge to the current configuration. The five truss spans were replaced with two new riveted Warren Through Truss spans, as well as several beam spans.
Unfortunately, this greatly reduced the significance of this bridge. Unaltered, this would have been one of the more significant bridges over the Des Moines River.
Today, the deck girder spans still remain, approaching the modern trusses. Several upgrades have been made to the substructures of the bridge since.

JohnMarvigBridges
[I wonder why BNSF went back to rivets. Generally, high-strength bolts have been used since the 1970s.]

Friday, December 19, 2025

1914 Välkommen (Old Mill) Bridge over Smoky Hill River in Lindsborg, KS

(Archived Bridge Hunter; Bridge Hunter; Historic BridgesSatellite)

I discovered this bridge while looking for the Old Mill Museum.

Street View, Mar 2014

Note the 2014 date on the street view above. It is now closed to vehicle traffic.
HistoricBridges, 2017 photo by Robert Elder
This 257' (78m) long bridge has a main span of 120' (36.6m).

Photo by Robert Elder via BridgeHunter

It is not pin connected. The 1989 rehabilitation kept the original railings. 
Street View, Mar 2014

1899 BPRR/B&O/BR&P Trestle over Little Mahoning Creek near Goodville near Dayton, PA

(Archived Bridge Hunter; Bridge Hunter; no Historic Bridges; HAER; Satellite)
BPRR/BR&P over Mahoning Creek: (Satellite)

I added "near Dayton, PA" because all of the Goodvilles that I could find on modern maps did not include this one. The BR&P Goodville has disappeared.

The bridge is 1000' (305m) long with a main span of 120' (36.6m). [BridgeHunter]

The Buffalo Rochester and Pittsburgh Railway Company posted
The Flyer crossing Little Mahoning Creek at Goodville Pa circa 1900. The locomotive appears to be one of the beautiful ten wheelers.

Dennis DeBruler commented on the above post

The railroad crossed the Mahoning Creek a little east of this crossing.
1909/09 Smicksburg Quad @ 62,500

You can see that the bridge over the Little Mahoning Creek still has its towers.
Satellite

The bridge to the east has concrete piers. The trees block getting a decent street view.
Satellite

This is on the route between the B&O mainline and DuBois.
Rumsey via Dennis DeBruler

Thursday, December 18, 2025

1950,2015 Abram Piatt Andrew and 1907,1981 Blynman Canal Bridges in Gloucester, MA

Andrew: (Archived Bridge Hunter; Bridge Hunter is broken; no Historic Bridges; Satellite)
Blynman: (Archived Bridge Hunter; Bridge Hunter is broken; no Historic Bridges; Satellite)

Abram Piatt Andrew Bridge


Jonathan Ross, Sep 2025

Bigtom Brancaleone posted two photos.
Gil B Guerin: The A. Piatt Andrew.
1

2

This 862' (263m) long bridge has a main span of 420' (128m). [ArchviedBridgeHunter_Andrew]

It had a much-needed rehabilitation in 2015. 
5:30 video @ 1:14 via Archived Cianbro
The repairs were done while traffic continued to use the bridge. They replaced one brace at a time by installing a temporary brace, demoing the old brace, installing the new brace and then moving the temporary brace to the next position to be replaced.

Blynman Canal Bridge


I found this bridge while looking for the arch bridge. It is interesting that they used two short leaves rather than one more normal length leaf.
The length of the bridge is 90' (27m). [ArchivedBridgeHunter_Blynman]
2013 photo by C Hanchey via ArchivedBridgeHunter_Blynman, License: Creative Commons Attribution-NonCommercial (CC BY-NC)

1951 37mw Lake Whitney Dam on Brazos River near Whitney, TX

(Satellite)

USACE, Fort Worth District posted
#OTD [Dec 10] in 1951 deliberate impoundment began at Whitney Lake. The main dam and spillway were completed eight months earlier in April.

W Boz, Aug 2021

USACE_recreation

As with many dams in Texas and Oklahoma, water supply is one of the purposes of this dam. It has two 15mw generating units. [tshaonline]
It was funded for flood control and power generation. But after the drought in the 1950s, water conservation was added to its function.

The 17,694' (5.4km) long dam is an earth embankment with a large concrete spillway. The spillway crest "(top of ultimate power pool)" is at 533'. 533' is also the conservation pool level. The flood pool is at 571', and the maximum design level is two feet higher. "The tops of the dam are at elevation of 584.0 feet and 580.0 feet above mean sea level for the concrete dam and the earth embankment, respectively." [twdb]
I've never seen a "top of ultimate power pool" specification before. Normally one sees a power pool elevation that is significantly below the conservation level. They have to quit generating power if the elevation drops below that because the head is too small for the turbines to function properly. In this case, it seems the turbines have to shut down if the head becomes too large.
I could not find a capacity figure for the spillway.

"All that water is held back by what is described as a rolled earth, concrete and steel structure that totals 17,695 feet long, 1,674 feet [510m] of that being the concrete structure, is 166-feet [51m]-tall and at the top is 34-feet 7.3m]-wide. But at the base, Beasley said, the concrete, reinforced by huge steel rebar, is 735-feet [224m]-thick." Each Kaplan turbine is supplied water by a 16' (5m) diameter penstock. "The [2017] upgrade resulted in an increase of from 20,700 kW to 37,000 kW in each generator at a 6-percent reduction in production cost....Except for internal parts like brushes and ball bearings, every piece of both Allis-Chalmers turbine and generator systems is exactly what was installed originally." [kwtx]

Note that this graph is water storage, not elevation. We can see the "bumps" caused by the heavy rains Texas had in the Summer of 2025.
WaterDataForTexas

I did find an elevation graph. It easily handled the rains of 2025 since the flood pool is 571'.
WaterData

WacoHistory
The dam provides flood control for Waco.

Fort Worth District, U.S. Army Corps of Engineers posted

One issue with flood control dams is to control development along the conservation pool for recreation. It is important that all such development be designed to withstand flooding. Because the main purpose of the dam is to flood those areas during heavy rains. The development is typically things like boat ramps, park benches, pavilions, etc. that can easily be power washed and returned to use after a flood. And campgrounds so that people can move out of the area during heavy rains.
This was the master plan for use of land between the conservation and flood pools.
USACE_public_meeting

This is the new master plan released in 2017.
USACE_final_report

1925 111mw Lower Baker Dam

(Satellite)

king5
Puget Sound Energy spent $170m to save the fish. That translates to the customers paying an extra dollar each month.

It looks like the gates are sluice gates.

vertical-access
"Completed in 1925, Lower Baker Dam is a concrete gravity-arch dam at the south end of Lake Shannon. The dam is 285 feet [87m] high and measures 550 feet [168m] across at the crest. Twenty-three spill gates run across the top of the dam, with non-overflow sections to the east and west of the spillway section."

pse
The powerhouses have a generating capacity of 111mw.

goskagit
Sirens are tested once a month in case people in Concrete, WA, need to evacuate the valley because of a dam emergency.

1906 BNSF/Great Northern Bridge over Skagit River at Mt. Vernon, WA

(Archived Bridge Hunter; Bridge Hunter; no Historic Bridges; Satellite)

The Skagit River has suffered record flooding in Dec 2025. I've seen videos of a temporary flood wall that Mt. Vernon installed along the river next to their downtown.

safe_image for Heavy Rainfall Causes BNSF Subdivision Closures in Washington (Updated 12/17) [paycount of 2, see the map below instead.]

Daniel Curtis, May 2016

The sandbar and grass on the north side of the river is under water.
Satellite

It looks like even the road is way under the water.
Street View, Sep 2021

rtands

Photo by Rich Murphy via ArchivedBridgeHunter, License: Creative Commons Attribution-NonCommercial (CC BY-NC)
The swing span has been fixed since 1965.

Tuesday, December 16, 2025

India's Tunnels under the Himalayan Mountains

I was aware of long tunnels under the Alps, but I was not aware that India is building so many long tunnels under the Himalayans. Unfortunately, the Himalayan Mountains have serious faults that make tunneling dangerous.

The B1M posted four images with the comment:
Digging deep. India is building its longest ever tunnel in one of the world’s most dangerous locations 😮
1

2

3

4

This video describes some of the tunneling efforts including the collapse of the Silkkyara Tunnel and the subsequent rescue of 41 people. Four rescue methods were launched in parallel. The auger method one.
13:40 video @ 4:14

The 9km Atal Tunnel has been completed.
@ 8:59

The 13km long Zojila Tunnel is currently being built. For it, they are using a new construction technique called the "New Austrian tunnelling Method." First of all, ground stability is monitored continuously. The construction uses rock bolts, steel ribs and shotcrete. Then they add a waterproof lining and another layer of concrete. This technique was used for the Silkkyara Tunnel, but they evidently did not properly adjust their approach as and when problems occurred.
@ 10:28