Sunday, February 04, 2007

Bridges Crossing the Truckee River

From: "Larry Hersh"

The original five bridges spanning the Truckee River, of the CPRR, were of wooden construction. The first, third, fourth and fifth crossings, were of what I call a Burr Arch type construction. These bridges were later covered to protect against dry rot. Now, for an interesting part of this discussion. The Second Crossing of the Truckee River bridge appears to be that of a Howe Truss type, with a pier in the middle between both trusses. Was it too, later covered as the other four bridges? By the way, today one can still see the original "angular slopes" of the bridge abutments toward the top, (Fourth and Fifth) which supported the Burr Arches. I have not explored the First and Third crossings as of yet, to hopefully find the same type of abutment design, unless they have been covered over with concrete, such as the western abutment of the Fifth Crossing. When the weather warms up, I hope to photograph these locations post same.

Also, if anyone has the resources, please scan with very high resolution, Hart #308. It appears to me that, along the grade to the right of the depot, showing the track on the fill material of the 5th Crossing (the bridge has not been build as of yet, it is not visible in this photo), if one looks carefully, locate the box car and then the water tank cars, etc. along the grade. Now look at the very far end of the consist, and it appears to me that a locomotive headed in a westbound direction may be on the "temporary bridge" trackage just below to the north of the crossing approach. Gamma correction may be needed to lighten up the photo. Or perhaps, the locomotive is stopped at the end of the fill material to the bridge.

—Larry Hersh


Blogger CPRR Discussion Group said...


I believe the term Burr arch bridge is not correctly applied to the Central Pacific bridges. Rather, I believe they are Howe truss bridges with Burr arches (when this feature is present). Note that several of the Howe patent drawings include arches.

I believe all the wooden bridges on the Central Pacific were covered after initial construction.

I think that documenting the original surviving abutments with both photos and scale drawings would be really valuable, particularly to capture the information in the designs to accommodate the Burr arches on the Howe trusses.

My copy of Hart 308 isn't clear enough to comment. I know Bob Spude of the National Park Service studied standard Central Pacific yard designs, including at Wadsworth (site of Hart 308). I'd suggest checking that info out.


2/04/2007 9:57 PM  
Blogger CPRR Discussion Group said...

From: "Wendell Huffman"
Subject: Bridges Crossing the Truckee River

Please help me figure out the sequence of bridges along the Truckee.

The railroad approaches the left (north) bank of the Truckee River at Truckee. Hart 221, 222, and 223 are in this section.

At Boca the RR crossed the Little Truckee (Hart 265).

At Eagle Gap (mp 133) the RR crossed over to the right (south at that point) bank of the Truckee. Hart 224, 225, 226, 273, 274. It some of these photos it appears that there is a second bridge here. WHAT WAS BEING CROSSED?

At Camp 24 the RR crossed back to the left bank – the Second Crossing. This was just east of tunnel 15 and just east of the old state line. Hart 267, 268, 269, 270, 271, 272.

Above (south of) Verdi the RR crossed back over to the right – 3rd crossing. Is there a Hart image of this crossing?

Between Verdi and Reno it crossed to the left bank – 4th crossing (Hart 278?)

The 5th crossing – at Wadsworth?


2/05/2007 1:13 PM  
Blogger CPRR Discussion Group said...


Some addendums to the corrections – it never pays to be overenthusiastic.



Page 27, photo caption:

"This is a Howe truss bridge across river at eagle gap."

This is another of A. A. Hart's original photographs #274 which was originally captioned "Bridge at Eagle Gap." The bridge is more accurately described as a "Burr Truss bridge" because of the arch through the members.

Actually, I'd describe this bridge as a Howe truss reinforced with a Burr arch. Burr's truss design was quite different.

Burr patent x2769, 1817

Howe patents 1685, 1840; 1711, 1840, reissued re175, 1850; 4726, 1846 (this one most significant)

Page 58, paragraph 3:

"On August 9 [1855] the first rail laid west of the Missouri [River] and the first in California was laid."

There were at least two railroads in California with iron rails before 1855. A contractors railroad in San Francisco even provided California's first railroad fatality in July 1851 with one S. Mellison crushed between a trains iron wheels and the iron rail. In 1853 a mining railroad with iron rail hauled ore from Virginia Hill to Auburn Ravine in Placer County.

However, it is worth noting that both of these early lines were animal powered and not steam powered - and that they might more commonly be described as 'tramway" rather than railways. Also not mentioned is the Arcata & Mad River, incorporated as the Union Wharf and Plank Walk Company on Dec. 15, 1854 with a horse-powered common carrier wood rail line, which is commonly considered to be the first railroad in California (although clearly not the first used of railed vehicles).

Page 69, paragraph 1:

"[Theodore D.] Judah, the man who built the suspension bridge at Niagara Falls"

"Theodore D. Judah was the Chief Engineer of the Niagara Gorge railroad which ran from Niagara Falls to Lewiston. The Niagara falls suspension bridge was designed and built in 1853 by John A. Roebling, who later built the Brooklyn Bridge."

If we are to be picky, the Brooklyn Bridge was designed by John Roebling, and construction started before John's untimely death. It was largely finished under his son, Washington A. Roebling, with able assistance by Washington's wife, Emily, who served as his eyes, ears and mouth on the job when Washington was laid up for an extended period with the bends during much of the construction.

2/07/2007 10:10 AM  
Blogger CPRR Discussion Group said...

To: Eric DeLony


What type of bridge is this? – see photo ...


Bob Spude – Historian – Cultural Resources Management – National Park Service – Intermountain Region – 505.988.6770 Voice – 505.988.6876 Fax

The National Park Service cares for special places saved by the American people so that all may experience our heritage.

2/07/2007 10:11 AM  
Blogger CPRR Discussion Group said...

From: "Eric DeLony"

It's a classic Howe-arched truss largely pioneered and used by the railroads. Many examples were built, but few remain today – Bridgeport CB (1862) in CA would be an extant example. I'm not aware of any without siding.


2/07/2007 10:12 AM  
Blogger CPRR Discussion Group said...

Subject: Bridge Designs

Eric DeLony, former head of the Historic American Engineering Record (HAER), and noted bridge authority, was asked his opinion about what to call the Central Pacific bridges with the arches. His comments are [above].

I also checked the HAER package on the Bridgeport Bridge – likely the last truss bridge out West with an arch. They refer to it as a Howe truss bridge with an auxiliary arch.

Bridgeport Covered Bridge, Spanning South Fork of Yuba River at bypassed section of Pleasant Valley Road (originally Virginia Turnpike) in South Yuba River State Park, Bridgeport, Nevada County, CA

Burr was apparently the first to add the arch to a truss bridge, and they are commonly called Burr truss bridges, but this isn't really accurate since many different truss designs have had arches added to them. Burr's patent was for his own truss design (very different from a Howe truss), but included the arch as well. However, Howe also included an arch in at least one of his patent designs. I will say, however, that the arch on the CP bridges does appear to have the characteristics of the original Burr design as opposed to what Howe showed.


2/07/2007 10:13 AM  
Blogger CPRR Discussion Group said...

From: "Larry Mullaly"
Subject: Re: Bridge Designs

I believe tha there is a pedigree story out there somewhere behind SP’s large-span wooden bridges. I think we need to look to earlier experiences of Arthur Brown. In the Brown letter file at CSRM there is a brief biography of this important, but somewhat under-recognized figure:

"Arthur Brown was born near Aberdeen, Scotland and raised by a widowed mother in Ottowa Canada. He went to work with an uncle, Alexander Christie, in constructing railroad bridges and culverts. They went to the Fraser River country in British Columbia and in 1864 Brown went to California and got a job with the CPRR under Stowbridge. In one month he had been put in charge of bridges and buildings.

Accomplishments: Rebuilding the American River Bridge 40 hours after it burned; designing and building the snow sheds over the Sierra, building mansions for Stanford and Crocker and the Del Monte Hotel; designing the "Solano"; supervising the building of the bridges and buildings for the entire Southern Pacific, through San Joaquin Valley and north of Redding into California.

Known for having bridges built in such a timely fashion as to never delay the grading and track laying work of the road. Pp. 86, 90-91 of John D. Galloway’s The First Transcontinental Railroad"

Given Brown’s lack of formal engineering training, these great wooden structures may well derive from the practical expertise of a craft tradition, rather than from technical manuals. There may well be a string of somewhat similar designs found in the work of Brown’s uncle, Alexander Christie. At very least this is an interesting hypothesis, suggesting that the "Burr truss" style of bridge building may have been around much longer than is commonly assumed.

—Larry Mullaly

2/07/2007 6:54 PM  
Blogger CPRR Discussion Group said...

Subject: Bridge Designs

Brown is certainly an interesting figure. But he didn't originate the CP bridge design. Burr's original patent with the arch was in 1819. Howe was in the 1840s (with an arch). More locally, the Bridgeport wagon bridge (still standing on the South Yuba) is a Howe truss with a Burr arch, and was built in 1862. And the Pennsylvania RR used several truss designs with Burr arches in the 1850s, including Howe. Judah's California Central bridge at Folsom was a Hall truss, and incorporated a Burr arch. ...


2/08/2007 12:46 AM  
Blogger CPRR Discussion Group said...

From: "Chris Graves"

... Remember the 1858 Coroners Jury verdict that I surfaced some time ago? It was signed by Theo. D. Judah, as Jury Foreman. Also on that jury, as validated by his signature on the verdict, is D D Kingsbury, the builder of the bridge in Folsom that Kyle mentioned. Mr. Kingsbury was also the builder of Kingsbury Grade, running between Lake Tahoe and Genoa, Nev.


2/08/2007 1:06 PM  
Blogger CPRR Discussion Group said...

From: "Wendell Huffman"

Other individuals to watch for for bridge traditions was I.M. Hubbard and Jesse George Baker. They built the first CP bridge across the American River at Sacramento. Baker died in 1864 as a result of injuries sustained when the [steamship] "Washoe" exploded racing "Yosemite" on the Sacramento River. Both were previously employed on the California Central bridge across the American River at Folsom (another [bridge] with an arch). Hubbard and Baker were also involved in the construction of the first transcontinental telegraph. Hubbard built the improved wharf facilities at Sacramento and I suspect was involved in other construction activities. I do not know of any association with Brown, but there may be some. I have yet to verify it, but I believe Baker was involved with Judah in the 1861 survey over Donner. Certainly Hubbard's name appears several places in Judah's expense ledger. Apparently they ate and drank together frequently. Hubbard was related to Upson – I believe his daughter married Loren Upson.


2/08/2007 1:23 PM  
Anonymous Anonymous said...

The main difference in the arch between the Burr pattern and the Howe Improved Truss is the connection between the truss and the arch and the point of that attachment.

In the Burr arch, the arch and the truss are tied together at the vertical and leaning timbers with bolts. In the Howe Improved truss, the arch is tied to the truss through tie rods that attach from the arch to the lower chord or bottom of the bridge (either radially or vertically).
See the google book: The apprentice, or First book for mechanics, machinists, and engineers - Page 161

As best as I can tell, from zooming in on the high-resolution digital photo scans I have of the Truckee River bridges, the arches are tied together with bolts but are not tied to the vertical/canted truss beams but only to the bottom of the truss through a "hacmatac" (the iron or wood angle brace) and a bar across the bottom. The bolts can be seen to pass between the arches without going through the truss timbers.
Interestingly, the Bridgeport bridge in California seems to be a combination of Howe and Burr connections.

From what I have read, the Improved Howe truss was good in theory but not so great in practice as differential expansion and contraction caused problems in synchronizing the arch and truss loads.

I have taken some measurements and photos of the south abutment of the Truckee river bridge at Wadsworth. Nothing very scientific but if anyone would like to go back sometime to make better measurements I would be happy to help.

-John A. Duffy - Reno Nevada.

6/01/2010 3:25 PM  
Blogger CPRR Discussion Group said...


In describing truss bridges with arches, the primary descriptor seems to be the form of the truss. While various patents include differing methods of connecting arches, in modern practice this seems not to be so significant - they are often all referred to generically as "Burr arches".

Thus the Central Pacific bridges with arches are often referred to as Howe trusses with Burr arches. Same for the Bridgeport bridge.

—Kyle Wyatt

6/04/2010 2:17 AM  
Anonymous Anonymous said...


I have to agree that it is trivial especially now. I frequently run across incorrect descriptions while I am looking for information on these bridge designs.

The manuals and design books contemporary to the building of these brides do call out the differences between the two practices. Frequently the writers, Byrne for one, are quite negative in their opinion of this type of bridge design.

For example, see "The Apprentice or first book for mechanics, machinists and engineers" by Oliver Byrne published 1860 on page 159 through 161.
The “Report for the Commissioners of Victoria” on Page 40 describes an improved Howe truss bridge for the Philadelphia and Reading Railway in a positive manner however. I have found side view plans for this one which has really helped me on my CAD design.

John A. Duffy - Reno, Nevada

6/05/2010 3:11 AM  

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