Today’s Durango & Silverton Narrow Gauge Railroad has the Denver & Rio Grande Western Railroad to thank for its 45 mile branch of track through some of the most remote and beautiful mountain country in the United States. Replacing a bridge such as 495A built by the Rio Grande is not taken lightly as it is an historic structure serving a truly historic railroad. While the Durango & Silverton takes its roots from the Denver & Rio Grande, it is not a recreation of the latter. It is instead a continuation of this profound line of railroad. The Denver & Rio Grande replaced or redesigned the bridge located at milepost 495.24 multiple times in the 19^th and 20^th centuries, not to mention has redesigned or replaced each of the bridges along this section of railroad during its 142-year history. The Durango & Silverton undertaking the same task today is not only a creation of the Durango & Silverton’s own history, but also a more accurate representation of history than any recreation could ever be. It is a true step back into history that the railroad faces the same challenges today as it did over 100 years ago.

As covered in Part 1 of this series, the Denver & Rio Grande Western had faced the challenge of replacing bridges many times before, giving the Durango & Silverton an opportunity to look back and to learn how it had been accomplished. Not only does looking back allow the railroad to learn from past failures and successes, but it also serves to keep the railroad in touch with its own history. The Durango & Silverton did not have to search far, either in distance or in time to find a fine example of a similar project on the Silverton branch.

Just over five miles to the south of bridge 495A, the Denver & Rio Grande replaced a timber and steel structure which spanned the Animas River near Elk Park at milepost 489.88 (489A) in 1964. The old bridge at Elk Park which was surpassed is still in place to this day. One of the greatest factors which led to the replacement of bridge 489A was the settling of the timber substructure into the Animas Riverbed. To repair this bridge, it would have been necessary to remove the entire structure to rebuild the substructure support. This is the identical issue faced when repairing versus replacing of the bridge at 495.24 was contemplated by the Durango & Silverton 60 years later.

“Old” Bridge 489 A – Dick Bell Photograph

Instead of attempting to repair the substructure of the existing bridge, the Rio Grande elected to build a new bridge immediately downstream of the existing structure. The location of the new bridge and right of way deviation reduced the overall necessary length of the bridge by crossing the river at a sharper angle, however the new track alignment created a sharp and disadvantageous 90-degree curve at the north end of the bridge in order for the track to return to the existing alignment.

The new bridge built in 1964 is an open deck girder bridge, utilizing steel girders resting upon concrete piers and abutments. The Denver & Rio Grande and the Durango & Silverton alike have benefitted from this structure and it has proven through the test of time that it provides the reliability and resilience which the railroad depends on. As of 2023 the bridge is 59 years old and has required minimal maintenance during that time. As an added bonus, deck girder bridges tend to be very picturesque as none of the structure blocks the view of the train passing over it, nor is the view obstructed for passengers crossing over the river on board the train.

“New” Bridge 489A – Dick Bell Photograph

When it came time for choosing a design for the replacement bridge to be built at 495.24, the Durango & Silverton weighed the combination of the success of the 1964 replacement bridge at Elk Park, as well as the fact that the existing timber structure to be replaced at milepost 495.24 was of open deck girder design. A steel and concrete open deck design quickly became the clear choice for the new bridge. Such a design possessed several key benefits. It would help to keep the aesthetics of this bridge and surrounding area similar to the original. Also, the railroad had a proven positive history with the bridge at Elk Park. Not only did the bridge at Elk Park provide a proof of concept, but it was also a nod to the history of the Silverton branch by building a bridge which mimicked the design chosen by the Denver & Rio Grande over half a century ago.

Bridge 495A – Anthony D’Amato Photograph

With a desired conceptual design developed, the Durango & Silverton turned its attention to other logistical challenges surrounding the project. The first and most obvious of which was fairly simple, snow. The project location is just under two miles south of the Silverton depot and sits at an elevation of 9,204 feet. Silverton averages over 150 inches of snowfall each winter, and a good year can yield over 200 inches. It is common for two to four feet to be on the ground at a given time, the Animas River flows year-round, but it is common for a majority of the river to be frozen over. The Durango & Silverton does not operate passenger trains to Silverton from November through April. This would make for an ideal time for this work to take place if it wasn’t for the uncertainty of weather. Construction season is also excursion season for trains bound for Silverton, and cancelling trains to Silverton for a bridge replacement was never an option.

To build the bridge during favorable weather conditions without interruption to train traffic, it would be necessary to build the new bridge parallel to this existing and realign the approaches to the bridge once completed. This would be once again similar to the bridge replacement at Elk Park. However, the Durango & Silverton still deals with the sharp curve created by the track realignment of that project, and it was of the utmost importance that the new alignment did not hinder the speed of trains through this section of track. Several alignments and locations were explored and tweaked, it was decided that the new bridge would be built parallel to the existing and just fifteen feet upstream. The new alignment actually decreased the track curvature to the south, and to the north, it would add a slight “S” curve to bring the track back to its original alignment. However, the reverse curve on the north approach could be executed gradually and without the need for sharp curves and speed reductions. The last challenge of realigning the track to this location was a rock outcropping on the south end standing in the way of where the new track needed to be placed. This, however, could be taken care of in the same way in which much of the Silverton branch was built by the Denver & Rio Grande, dynamite.

The Durango & Silverton began work with a number of contractors in bridge design, construction technique, blasting, river hydraulics, wetlands, and associated environmental review. Conceptual drawings were created, wetlands delineated, and the general scope of the project was refined.

Conceptual Drawings

While many similarities were taken from the Elk Park bridge, the new bridge at 495.24 would have some stark differences as well, due to how the Animas River and the tracks meet at this location. The elevation of the track possesses less clearance or “freeboard” above the water than it does at Elk Park, and the tracks do not cross the river as perpendicularly. The lower level of the track meant that in order to maintain adequate clearance between the low point of the girders and the high point of water, the girders had to be smaller. The track over the bridge could be raised, but not to the full extent required to keep the bridge safety above the water flow in the event of flooding. Smaller girders means that more support is necessary. As can be seen from the conceptual drawings, the new bridge would utilize nine piers of support, the Elk Park bridge utilizes just three. The piers of the Elk Park bridge are concrete which was poured in place into the riverbed. While these piers are a great support structure, they have a large surface area in the water and are exposed to the river’s hydraulic force as the water flows past. Placing nine poured concrete piers under bridge 495A would put a large footprint into the river and increase the forces to which it was exposed. Instead, each of the piers would be supported by 14”  H pile and concrete pier caps would be cast off site and set into the place on top of the piling. This gives the bridge the support it needs and only has a footprint of 36.75 square feet in the river for the entire structure, an even smaller footprint than just the three piers at Elk Park create.

With the conceptual design and location of the bridge complete, one large question remained. What to do with the existing bridge once the new bridge is complete? As mentioned in the first paragraph, replacing, or affecting a structure such as bridge 495A is not something the Durango & Silverton takes lightly. The railroad is proud of its history and heritage and strives to keep both intact. In the case of the Elk Park replacement, the Rio Grande elected to leave the existing structure in place without track over it. To date, this decision has been inconsequential. The Durango & Silverton debated on whether to leave the existing Animas River Bridge in place for interpretation and to pay homage to the railroaders of years past who built the bridge, or if doing so could create unintended consequences in the future. In the end, the railroad elected to let the Animas River decide.

The Durango & Silverton contracted with a firm specializing in river hydraulics. By using information from several site visits as well as the United States Geological Survey Light Detection and Ranging (LiDAR) data, cross sectional areas of the Animas River at the bridge site were modeled under the conditions of potential flooding events. As mentioned in part 1 of this treatise, the supports of the existing bridge were never driven down into the river bottom. Instead, the bridge simply rested on mud sills which sit on the base of the Animas River. A check dam or “weir” was built just south of the bridge to provide stability under the mudsills and to slow water flow under the bridge, reducing scour. While the weir did its job to slow water flow, it also created an unnatural shelf in the riverbed, pushing both the base of the river and the water above it upwards. The shelf reduced the freeboard of the existing bridge to the point that in a one hundred year flood (1% AC), the river would contact and even overtop the southern portion of both the existing and the new bridge.

Existing Bridge and Check Dam – Matt Cunningham Photograph

When this scenario was produced from the hydraulic study results, it was clear that in order for the new bridge to maintain adequate clearance above the water in the flood event, the weir needed to be removed. Removing the weir possessed benefits outside of railroad purposes. It would remove an unnatural, manmade barrier in the river which had an affect on water flow, and wildlife. By removing the dam, the Animas River would be allowed to flow naturally. However, removing the weir also meant that the velocity of the water under the existing bridge would increase, therefore increasing scour and could destabilize the footings of the old bridge. The likelihood of the old timber components washing out increased, creating a liability for the railroad. By virtue of the check dam requiring removal, the old bridge needed to be removed as well.

Over the course of three years, the railroad conceptualized and refined the bridge replacement project scope as well as searched and applied for funding sources which could help the railroad with the cost of the project. In July of 2020, the railroad was awarded a grant from the Federal Railroad Administration’s Consolidated Rail Infrastructure and Safety Improvements program. Three years of additional planning, design, and permitting lay ahead, but with the help of the Federal Railroad Administration, the project officially had the green light and began forging its path towards construction scheduled to commence in the fall of 2023.

In 1860 Charles Baker led a prospecting party into the caldera which eventually became known as Baker’s Park. In 1874 the township of Silverton was laid out on the valley floor of the caldera, the town receiving its name for the mineral deposits which had since been discovered in 1869 by Baker’s party among others. Mining operations sprung up in a hurry during this time as gold, silver, zinc, copper, aluminum, iron, and other precious metals were discovered in the area. By 1880 Silverton had become a booming mining town.

The Denver and Rio Grande Railroad arrived in the area near Animas City Colorado in 1881. The railroad quickly established the company town of Durango just south of Animas City and began building a branch line north to Silverton to haul the mining riches back to Durango. The branch between Durango and Silverton was completed in just nine months and five days, arriving in Silverton in July of 1882. While completing 45 miles of track in just over nine months is an extraordinary feat, it is important to remember that mining booms and gold rushes such as the California rush of 1849 and later, the Klondike rush of 1896 didn’t last a long time and it was important for the Rio Grande to get to Silverton fast and begin hauling ore south before the boom was over. The railroad was not in great financial shape at the time either and just two years after reaching Silverton, the Denver and Rio Grande fell into receivership for the first time in July 1884. Both factors meant that speed was the key to construction, not necessarily quality, including right of way, track, and bridges. Just because the line was completed did not mean that it was capable of self-sustaining for the long-term future.

Bridge work and even bridge replacement is nothing new to the Silverton branch. Due in part to the speed in which the railroad was built, each of the 29 bridges between Durango and Silverton have received major work or have been replaced. Many of the bridges found on the line were constructed for other locations on the Rio Grande system and were relocated to their present site. The 15th Street bridge just north of downtown Durango was replaced between 1917 and 1928 with bridges from other locations and the wrought iron deck truss referred to as the “High Bridge” was brought to its current location in 1894 and received major reinforcement work in 1981.

The bridge located at milepost 495.24 on the Silverton branch is no different. Common with  railroad nomenclature, this is bridge 495A. “495” being the milepost which the bridge is located  and “A” being the first bridge within that mile in ascending order. Even though the Silverton  branch crosses the Animas River five times, to most historians, railroad employees, and railfans  alike, the bridge at 495.24 has earned the name the “Animas River Bridge.” The history of this  bridge prior to 1932 is somewhat unknown to the Durango & Silverton. 

From the historic photo below, it appears that the bridge was originally constructed using an  open deck truss design.

From what can be gathered, it appears that this bridge was replaced in approximately 1901 by  one which utilized a combination of open deck wooden girders as well as two 60-foot-long Howe pony trusses. Trusses such as these are not uncommon on the Silverton branch, and  several remain to this day. Examples of these bridges can be found at the north end of the 15th St. bridge, Hermosa Creek bridge, as well as the old bridge bypassed in 1964 just south of Elk  Park.  

In 1932 the Howe pony trusses were removed and replaced with additional open deck timber  girders along with additional support creating more, but shorter spans. The bridge has seen  significant work over the years since 1932. Additional scour protection and support have been  added as well as a check dam, however the work performed in 1932 left the bridge in roughly the 

same configuration which it remains in today. The work undertaken over the years resulted in a  242-foot open deck timber girder bridge with varying span lengths and span designs. 

It is no stretch of the imagination to think that the railroaders who performed this work on bridge  495A would never have imagined that the railroad, let alone the bridge would still be utilized  into the 21st century. It must be remembered that when this work was completed, the United  States was in the depression, and rail traffic on the Silverton branch was dwindling. To state that  the future of the railroad was unknown is an understatement. 

Instead, the Silverton branch continued to survive through the 1940’s, 50’s, 60’s, and 70’s thanks  to a newly developing market – tourism. The very automobiles and roads which spelled disaster  to many railroads in the United States during that period allowed people the opportunity to come  ride this spectacular 45 miles of railroad which many of them had seen featured in Hollywood  

films. Even once the railroad was sold by the Rio Grande in 1981 to the newly formed Durango  & Silverton Narrow Gauge Railroad, the bridge continued to serve the trains passing over it.  

While the Durango & Silverton continued to make repairs to the structure over the years, bridge  495A never showed signs of excessive deflection, or failure of any kind. This is a true tribute to  the railroaders who designed and built this bridge nearly 100 years ago. However, as necessary  maintenance of the structure continued to increase and a 3rd party engineering in-depth study of  the D&SNG bridges concluded in 2017, it was jointly decided by the railroad and its consulting  

bridge engineers that more drastic steps were needed to ensure the long-term reliability and  safety of trains passing over the Animas River at this location. 

The Durango & Silverton immediately began exploring a plethora of options. Repair, retrofit,  and replacement were all considered. However, as repair and retrofit options were analyzed, the  same issue kept rising to the surface the substructure or support portion of bridge 495A. Not  unlike many bridges of that time, the base of the bridge was not driven into the bottom of the  Animas River. Instead, the bridge was supported by mudsills which simply rest on the floor of  the river. This is why the check dam was built immediately downstream of the bridge, to  stabilize the floor of the Animas River, and to slow down the flow of water under the bridge and  to reduce scour during times of high velocity runoff.

This meant that no matter what retrofits or improvements were made to the girders or piers, the  bridge would still simply rest on the floor of the river. Retrofitting the mud sills with driven  piling meant removing the entire bridge above it. This quickly began to blur the line between  retrofit and replacement of the bridge. By the time all options had been explored, the answer  became clear. To accomplish this project correctly and ensure the long-term resilience of the  bridge and the railroad, it was once again time to replace bridge 495A. In a twist of history  repeating itself, the Durango & Silverton reached the same decision that the Denver and Rio  Grande had arrived at numerous times before nearly 100 years ago.

Exciting news out of the D&SNG roundhouse this week: 

K-28 number 478, which first entered service in October 1923 for the Denver and Rio Grande Railroad, will 100 years later be returned to service. 

“Over the past few years the D&SNG has continued to see record ridership, which has resulted in daily scheduled doubleheader trains. That continued growth and need for regular doubleheaders is what makes returning the 478 to service a natural choice.” says D&SNG general manager Jeff Johnson. The 478 last saw service in April 2016 and has been on display in the D&SNG’s Roundhouse Museum ever since. Work to return the 478 to service is expected to begin in early 2024 and take between 24 to 36 months to complete. Aside from the standard Federal Railroad Administration Form 4 requirements, work will also include a conversion to burn oil. 

In addition to the 478 returning to the active roster, the D&SNG is also expecting this coming winter to see the last regular use of coal. The D&SNG’s last active coal burning locomotive, number 481, will see its final winter as a coal burning engine before undergoing a conversion to burn oil later in 2024. “A few years ago I always thought we would want to keep a coal burner,” said Randy Babcock, AHR Chief Mechanical Officer “the reality is that it just doesn’t make business sense to maintain a locomotive that we only intend to use a quarter of the year.” 

Conversion of the 481, along with the return to service of the 478 will ultimately give the D&SNG an active roster of seven operational oil-fired locomotives – 473, 476, 478, 480, 481, 482, and 493. Additionally, locomotive 486 will remain on display in the D&SNG Roundhouse Museum.

Through an ongoing partnership with Hinsdale County Historical Society and the people of Lake City, CO the Durango and Silverton Railroad is proud to be able to provide periodic updates on the restoration of former Denver and Rio Grande combine 211.

Car 211 was originally constructed by Jackson and Sharp in 1881 for the D&RG as coach number 74. Later renumbered 298, the car served as a standard coach until it was converted to a combine (half coach – half baggage car) in 1900 for use on the branch lines of the D&RG. Being able to seat 22 passengers and handle the mail and a small amount of freight, a car of the 211’s design was ideally suited to handle the limited traffic on some of the most rust covered, weed choked, light weight rails of the D&RG’s system, such as the Lake City branch.

With the Lake City branch abandonment in 1933, and an ever-decreasing need for a combine car on other routes, the 211 found fewer opportunities for work until it was finally declared surplus and was stricken from the roster in the early 1940’s. Its trucks and metal parts removed, 211 spent most of the next 75 years moving from place to place within Colorado,
first as a chicken coop, then as a derelict artifact, until finally in 2017 it was brought back home to Lake City. In 2021, Lake City’s Hinsdale County Historical Society contracted with the Durango and Silverton Railroad to restore car 211 to its late 1920’s appearance. Work began in Lake City with a full assessment of the car followed by fabrication of bolsters and truss rods in order to set the car back on wheels.

In August 2022, the 211 was transported to Durango to begin its full restoration, which is currently ongoing and expected to last into 2024. Funding for the first stages of the project has come through donations and grant monies from the Colorado State Historic Fund, National Trust for Historic Preservation and El Pomar Foundation.

For additional information visit the Hinsdale County Historical Society visit: https://lakecitymuseum.com
To help support this project, donations can be made at https://lakecitymuseum.com/railroad-car-211

Updated December 16th, 2022.

The Durango & Silverton Narrow Gauge Railroad is a 137 year old historical treasure, a once-in-a-lifetime bucket list experiential adventure for thousands of passengers each year. It provides an unparalleled opportunity to experience, in a very visceral way, one of the last surviving narrow gauge trains and simultaneously connect with the wild and unspoiled beauty of nature while riding through the pristine wilderness of the San Juan National Forest. And because of this, has been the conduit for many unforgettable moments of joy.

But what does it take to conserve this historical treasure that showcases nature so well and is beloved by so many? This year, 2018, will go down as one of the most challenging years in the railroad’s history.  First there was the 416 fire, then severe thunderstorms, then mudslides, which washed out track resulting in the disruption of train service.  In fact, the Durango & Silverton Narrow Gauge Railroad was shut down for more than 40 days over this past summer as a result of these incredible forces of nature.

Click here to view recent track repairs: Click Here

While this year’s events have been challenging, this is not the first time the railroad has had to overcome and persevere. Indeed, events like these have brought about transformative changes in the evolution of operations of the railroad. These changes have helped to better conserve this historical treasure for future generations to enjoy in perpetuity.

It takes huge amounts of effort, time, expertise, and resources, not to mention conviction, drive, and passion to keep a national treasure like the Durango & Silverton Narrow Gauge Railroad operating for well over a century. In this blog series, we’d like to share with you more about the rich, unique and incredible history of the D&S as well as some of the upcoming changes that are planned for this National Historic Landmark. We invite you to join us!

Because of long-term drought conditions and changing climate patterns in Southwest Colorado, the Durango & Silverton Narrow Gauge Railroad is evolving its operations, in part, by diversifying its locomotive power so that it can more safely transport passengers year-round regardless of weather conditions.

Conversion of Locomotive 493 from Coal-Fired to Oil-Burning

Here is the tender tank for locomotive 493 under construction in Durango. The tender tank is nearing completion off site with construction of the drop-in 2485 gallon oil tank beginning soon thereafter.

Work on the Locomotive 493 conversion from coal-burning to oil-burning continues. Here’s the latest on this process.

All wheels have now been re-profiled. The one nearest the camera has a new axle; the others still need the journals turned and liners faced.

As discussed in previous posts, the Durango & Silverton Narrow Gauge Railroad‚ Locomotive #493 is in the process of being converted from coal-fired to oil-burning at the Durango depot in Durango, Colorado. But the actual mechanical work to restore and convert this locomotive to oil fire is only one aspect of being able to successfully operate the #493 on the D&SNG line. Crew training, fueling logistics, and estimating fuel consumption are also key elements in the transition from coal to oil. For this reason, the D&S railroad has leased a historic oil-burning locomotive, the Southern Pacific 18, a T44 16/20 68 locomotive, from Eastern California Museum in Inyo County, California.

Here is the rundown of recent work:

Approximately 175 flexible staybolts have been added so far. We’re a little over 1/3 done with the flexible staybolt conversion part of the project.