Category Archives: Prototype

Things to do with the Georgetown Branch prototype.

E.C. Keys Coal & Fuel Oil Trestle Model Project

April 2, 1956. Heading west down the Branch from the Junction. On the right is the long E.C. Keys warehouse atop the retaining wall. To the left of the train is the coal trestle lead track. The old B&O MOW X-358? M-15 boxcar is sitting on a storage track.
Photo by R. Mumford. B&ORRHS Collection.

(NOTE: UPDATED DRAWING TO v2 BELOW 7/3/2022) Just about a hundred yards west of Georgetown Junction was the Enos C. Keys & Sons company that sold building materials, aggregates, merchandise, coal and fuel oil from 1889 until 1978 when it finally went out of business. On the North side of the Georgetown Branch track, a turnout branched off and climbed up a steep embankment and sat atop a high retaining wall where it served a warehouse for building materials. Aggregates would be unloaded over the side of the retaining wall via chutes, down into large sorting bins below. On the south side of the GB tracks, a turnout diverged, rose slightly, and then out on a coal trestle that was approximately 227′ long (based on aerial images). This trestle also served as an unloading platform for fuel oil. In the very far northwest corner of the property, at the intersection of Brookville Rd & Stewart Av was the scale house, which was torn down recently. In a strange twist of fate, a fellow GB-served industry, T.W. Perry, is now occupying the E.C. Keys space atop the retaining wall. The lower area where the coal dock was is now a long warehouse building. Much of this will likely (or already has) change once the Purple Line construction is completed.

Feb 22, 1958. Heading to Georgetown. Another view of the trestle lead and warehouse/retaining wall. This is the BEST photo I have of the coal trestle… and it’s not even in the photo! yep!
Photo by R. Mumford. B&ORRHS Collection.

For my model railroad, I am modeling the coal trestle, retaining wall and siding, and the long lumber warehouse.

The area around Georgetown Junction
This view of the layout should give you an idea of where things will go. The coal trestle is going where the small trestle is in this photo, the retaining wall will be along the high siding.

I decided to spend some time studying the site and develop a plan for my model of the trestle.

A snip of the 1957 aerial view from Historic Aerials. Note the fuel storage tanks to the southeast. The scale house was up in the upper left hand corner. Also note the boxcar sitting on the end of the retaining wall siding next to the lumber shed.

Using the scale tools available on the Historic Aerials site I was able to get basic measurements of the trestle. Approximately 227′ long, 15′ wide, bents (bins) about 15′ apart. This was enough to get me going, along with other details in the coal yard that I could observe. I now needed to figure out what sort of prototype to go after. Of course, without a photo I have no idea what the design of this trestle was derived from, but a good starting place was with the B&O Standard Plans book. I happened to have one that covers such things:

B&O Railroad, Roadway and Track Standards, 1945 (rev 1948); Commercial Coal Dump, Timber Construction. Book available from B&ORRHS, item 72047.

This fantastic reference book is available through the B&ORRHS Company Store, now in digital format. I highly recommend it! After some mocking up on my model railroad I realized that I wouldn’t be able to model a whole 227′ trestle and needed to reduce the size. I settled on a nice 135′ which will allow three 40′ cars, two less than the prototype would have held. This would work nicely for my small layout and even at this small size would still be a formidable structure. (I sure am building a lot of trestles on this layout… sheesh. I’ve got about four more to go, but that’s for another day!)

So, using Adobe Illustrator, the B&O plans and some photos I found online of similar structures & models, here is what I came up with:

So the image is quite wide – click for a larger view. I hope this gives you an idea of the design I’m after. I tried to stick as close as possible to the B&O design, but added a few modifications that I felt were necessary. One was the inclusion of additional supports for the walkway, a wider walkway, along with a railing. I also made some slight height adjustments but stayed within the requirements laid out in the B&O plan. All in all, I think it’s a good representation of the trestle and will make a very nice model. If you’d like a copy of the vector file, it’s below as a PDF for your own personal use. (NOTE: UPDATED to V2 7/3/2022)

The E.C. Keys facility will be a key scene on my layout. It’s a fascinating area to switch and this coal trestle will be a centerpiece of the small industrial area. Now to finish the Rock Creek trestle so I can get on with building this!

June 6, 1948 – The MSME Excursion Train

B&O MSME Special at Eckington Yard, Washington, DC, engine Q-1c 4320 with two passenger cars and four cabooses prepares to depart. E.L. Thompson photo, B&ORRHS collection.

Early on while conducting research on the Georgetown Branch I came across photos of a B&O steam excursion that took place on June 6, 1948 labeled as the “MSME Excursion.” From what I can tell the train was commissioned by the Metropolitan Society of Model Engineers, a prolific and very active model railroading group in the DC area. The train was assembled at the B&O’s Eckington, DC coach yard, where it departed and traveled west on the Metropolitan Branch, to Georgetown Junction where it entered the Georgetown Branch. The train made several stops, on its way to Georgetown and then would return to Eckington, DC. The MSME itself formed at some time in the early 1930s and resided in the “attic” of Union Station where they had a permanent model railroad layout. They would host National Model Railroad conventions, local model contests, other meetings and events, including railfan excursions. For this post, I will share what I know about the train that ran that day in 1948.

So far, I have yet to uncover a detailed account of the excursion events. My assessment is based on the photos that I have discovered and that have been shared with me. From what I can tell, the train was assembled in the B&O passenger or coach yard in Ivy City. The loco, 4320, was coupled up and the train headed out, engine-first, toward Georgetown Junction. There was a stop at the Rock Creek Trestle, where some chose to photograph the loco from below as it crossed this impressive trestle.

B&O Q1-c 4320 crossing Rock Creek, Jun 6, 1948. Collection of W. Duvall.

The next stop was at Chevy Chase, MD where the train paused on its way west, just past Connecticut Ave. Note how overgrown the yard was at this time.

B&O MSME Special at Chevy Chase, MD. E.L. Thompson photo, B&ORRHS collection.

From here, the train continued west, passing through Bethesda and on to Dalecarlia. Whether or not the train stopped in Bethesda, I do not know. The next stop seems to have been Dalecarlia Tunnel for a photo run-by of the train emerging from the tunnel. (photo below.) The train continued down along the palisades and would next pause at Fletcher’s Boathouse along the C&O Canal. I believe the train likely backed up as patrons hiked the short distance to the bridges over the Canal where they did a run-by or simply staged a photo.

I believe this is from the MSME excursion train. Photo from Impossible Challenge, Herbert H. Harwood, Jr., 1979, Barnard Roberts & Company publisher

After this pause, the train then continued on to Georgetown, where it terminated near the “new yard” for a break and a photo op.

Jun 6, 1948, James Martin collection, B&O RR Historical Society Archives collection.

At this point, the railroad did a bit of switching of the train, changing the order from:
<<West <[4320][baggage][4602][C-2312][C-2250][C-1995][C-2806]
[C-2312][C-2250][C-1995][C-2806][baggage][4602]<[4320] East>>
The loco would run tender-first back up the branch, at the head end of the train. You can see the rearranged train in these images:

B&O MSME Special mustering for departure from Georgetown, DC, the west end “long siding”. E.L. Thompson photo, B&ORRHS collection.
B&O MSME Special heading West, Jun 6, 1948, Photo by Lawrence Winnemore, B&O RR Historical Society collection.

This last image is a really special action shot, taken from the window of caboose C-2250 as 4320 works hard to pull the excursion uphill back toward home. If I had to guess, I’d say this was in the area of Dalecarlia, but I really can’t be sure. So let’s take a look at the individual players on the train.

B&O Q1-c 4320

Built in September, 1913 by Baldwin Locomotive Works, Mikado 4320 weighed in at 284,500 lbs. The loco was retired a few years later June 19, 1951 at the Mt. Clare shops, Baltimore, MD. When the excursion happened, it was likely one of the few steamers in the area still in service and probably only used for special occasions like this. At this point diesels were really becoming ubiquitous in the DC area.

4320 Emerging from Dalecarlia Tunnel, 6/6/48. Photo by Paul Westhaeffer, B&ORRHS Collection.

B&O REA Express Car, 17xx

B&O MSME Special at Chevy Chase, MD. E.L. Thompson photo, B&ORRHS collection.

Troop sleeper cars were built by Pullman during WWII to facilitate the movement of troops during the war. Afterwards, many were rebuilt into express baggage cars. Shops would cover and modify window and door openings, ends and other features to suit their needs. Unfortunately I don’t yet have a good side view of this car, so its actual number remains a mystery but is likely 17xx. Here’s a couple similar cars, found in the wonderful Barriger Library collection:

Thomas Underwood Coll B&O711
Railway Express Agency Car 1737 Camden Coach Yards, Baltimore, MD 10/27/1963
Thomas Underwood Coll B&O710
Express car 1722 ex-ww2 troop sleeper. Camden Station, Baltimore, MD 8/30/1968

B&O Coach 4602

B&O MSME Special at Georgetown, DC. E.L. Thompson photo, B&ORRHS collection.

Joe Nevin clued me in on this car. This is a class A-13, of vintage pre-1910 construction. The car sides had steel sheathing installed over the wood siding. By WWII these cars were in excursion and special use until returned to full service during the war. By 1947, they went back into special ops (like an excursion on the Georgetown Branch).

B&O I-16 Caboose C-2312

B&O C-2312 at Eckington Yard, Washington, DC. E.L. Thompson photo, B&ORRHS collection.

The I-16 class was converted from old M-13 class boxcars, for use during wartime service when steel was restricted. Many railroads built composite “wartime” cabooses during this period. Car is red, with white lettering and is looking fresh!

B&O I-5 Caboose C-2250

B&O C-2250 at Eckington Yard, Washington, DC. E.L. Thompson photo, B&ORRHS collection.

I-5 subclass, constructed ca 1929.

B&O I-5 Caboose C-1995

B&O C-1995 at Eckington Yard, Washington, DC. E.L. Thompson photo, B&ORRHS collection.

I-5 subclass built ca 1926. This caboose was spotted on freights that served the Georgetown Branch.

B&O I-12 Caboose C-2806

B&O C-2806 at Eckington Yard, Washington, DC. E.L. Thompson photo, B&ORRHS collection.

C-2806 I-12 subclass, built in 1945, all steel construction. Red with yellow lettering.

As for modeling this train, I have begun putting together my representation. Here is the approach so far:

  • Q1-c 4320: Precision Scale Q1-c. An exquisite model and really the “first” brass loco that I’ve owned. It needs a bit of work, as the mechanism is not super-smooth and it needs DCC/sound installed.
  • Express Baggage Car 17xx: I found an old Roller Bearing Models – Troop Baggage Door Car kit, #501 (see pic below), but it’s completely incorrect for this car. Joe N. told me that the Walthers model is from a C&O prototype and not quite correct for the B&O (the window spacing and door placement are wrong), but I think I’m going to seek one out and use it as a stand-in for now.
  • A-13 Coach 4602: To do this properly will be a challenge, as no models exist of this type of car. I have a stand-in Bachmann Spectrum heavyweight to use in the meantime.
  • I-16 C-2312: So far I have collected an old Pro Custom Hobbies wood/metal I-16 kit, and an Accurail 40′ double-sheathed boxcar and some additional detail parts to do my build. The B&O Modeler magazine (Vol 7, Number 4, Pg 5) featured an article by Chris Tilley on kitbashing an I-16 which I plan to follow.
  • I-5 2250 & 1995: I’m holding out for the Spring Mills Depot models, which I have faith will be coming in the future. I do have an I-5 Pacific Mountain Shops resin kit that I will build and use as a stand-in.
  • I-12 2806: I have a gorgeous SMD I-12 lettered correctly which I will use.

If you have more info on this special excursion train, I’d love to hear from you! I also welcome any comments and feedback on my own observations as well as my modeling choices/plans. I have additional photos of the train, but not the permission to publicly share them, so hopefully in the future I’ll get that book written and can get them out for all to enjoy.

Ditching Crew at Georgetown Junction, 1940

John King recently shared this absolutely magnificent photo of a ditching crew at work near Georgetown Jct ca 1940. The photo was taken by Leonard Rice.

Georgetown Jct Work Train with caboose C-1925, ca 1940. Leonard W. Rice photo, Collection of John King. All rights reserved.

John notes: Interesting to note that the 2-8-0 was NOT an E-27 but an E-31 which to my eye looks similar to an E-27 but was originally a C.H.& D. locomotive.

I tried placing the location of this photo and the best I can fathom is that it is East of the Junction (crossovers), closer to Silver Spring. I believe the track that the work train is on is the “Silver Spring Lead”; the long siding that extended from Silver Spring yard all the way along the mainline to a point just East of Talbot Ave bridge. The Georgetown Branch would be out of sight to the left, a mile or so ahead. Thank you, John, for sharing this rare and special color image!

Hot Shoppes HQ in 1959

This neat photo from 1959 of the front of the Hot Shoppes Inc. (later Marriott) HQ at 5161 River Rd was shared on the Bethesda Chevy Chase Back In The Day Facebook Group, by P. Wilson (Thanks!). The Georgetown Branch passed just behind the photographer, the siding that served the building was located just to the left of the building. In the distance to the right, we can see a boxcar spotted at the industry located next door on Landy Ln. I’m not certain what this industry was but they had a large loading hopper.

J. Willard Marriott and George Romney standing in front of the offices of Hot Shoppes, Inc. , 1959. Multimedia Archives, Special Collections, J. Willard Marriott Library, University of Utah, P0164 J. Willard and Alice Sheets Marriott Photograph Collection

Mystery Refrigerator Car in Bethesda, ca 1973

Rich Pearlman shared these four photos with me that he shot as a kid in Bethesda. The car is sitting on what was the passing siding/team track in Bethesda. Thanks to some wonderful sleuthing by folks over on the Freight Car Enthusiasts Facebook Group, the car was identified. This is a General American Railcar 40′ mechanical refrigerator car, built 9/1957. I can’t read the rebuild date but similar cars have dates in the 1971-75 range. I also can’t make out the reporting marks, but I believe they are URTX based on what the FB group revealed and other photos that are online of similar cars.

This is an oddball to me. This refrigerator car parked in the yard in downtown Bethesda. Why? At this point, I don’t know what industry was left in Bethesda. I don’t think Maloney was even receiving rail cars at this point and most of the others had departed long ago. There was some LCL service and I’m assuming that’s what this was. But for who? And what was it transporting? A mystery that will likely go unsolved. Would love to hear your thoughts! And, thanks again, Rich!

B&O FM H12-44 9725 Heading East at Georgetown Jct., April 5, 1966

B&O 9725-1 Silver Springs MD 04-05-66, By RNS
B&O 9725-1 Silver Springs [sic] MD 04-05-66, By RNS

This wonderful photo by Russ Strodtz on Flickr came via Jeffrey Sessa over on the Maryland Division Railfans FB group. My money is on the train likely being a load of empties coming off the branch, perhaps from Maloney in Georgetown or Bethesda. Curious if they’ll pick up some cars from the Junction and head East or pick up loads and head back to Georgetown. REALLY neat view of the E.C. Keys lumber shed in the background. Gives me some great info for when I build that model! Thanks, Jeffrey!

C&O Canal Trestles, Summer of ’86

C&O Canal Trestles, Summer of '86
Photo from Christopher Russell

Christopher Russell sent me this neat photo of the C&O Canal trestles shot in the summer of 1986. Of particular interest is the fresh ballast and what appears to be girder welded rail. As far as I know, the last train down the Branch happened in the summer of 1985. I had also heard rumor that Chessie/B&O decided to lay girder rail just before the abandonment took place. Maybe a case of the left hand not knowing what the right hand is doing? I know the Tom Thumb John Bull operated on this stretch in 1981 and thought maybe it was something similar. Anyone have any ideas? Was there a film or TV show shot on this stretch? The track would have been serviceable through the late 1980s so it could have been anything. Would love to hear your thoughts!

NOTE: Thanks Christopher for the corrections. I think I wrote this in a hurry and neglected to proofread it. Mea culpa!

Christmas Comes to Washington Via Georgetown

Over the years, I’ve shared a few photos I’ve come across depicting the National Christmas Tree resting in the B&O yard in Georgetown. (one, two, three) Beginning in 1954, the “Community Tree” would make its trek cross-country on a flat car or gondola; blocked, braced, packed and tied-up like a Christmas ham, the tree would arrive in DC to be transloaded onto a flatbed trailer and trucked through Washington to the National Mall where it would be craned into place, decorated and illuminated as the star attraction in the Pageant of Peace.

I was recently contacted via email by a member of the Forest History Society who so generously shared some photos (and a video!) related to Christmas trees in Georgetown. These images are REALLY cool and show some views that I’d never seen before. I am always really excited whenever I get to see new things related to the Branch! You can see all of their National Christmas Tree related images in their archives, here. They recently published a wonderful article on the journey the 1961 National Christmas Tree made from forest to the National Mall.

In these photos from FHS we see the 1960 tree having arrived in Georgetown being tended to by some staff members. This tree was cut in Oregon and traveled via SP/UP/CNW/B&O on an SP F-70-17 85′ flat car. In the first photo we see what must have been an arrival ceremony and even Santa has climbed on board and is wielding a “Seal of Approval” sign. In the next images we can see a large box surrounding the end of the tree, no doubt to protect it and keep it wet. We then see the tree being prepared for transloading to the adjacent flatbed trailer. Bonus video footage of the tree being prepared in Oregon for its voyage across the Country. The final images are the 1961 tree which came from Grays Harbor County, WA via NP/CB&Q/B&O on a TTX flatcar. All photos are courtesy of the Forest History Society, Durham, N.C.

Film footage of cutting of 1961 National Christmas Tree (film has no sound). The 1961 National Christmas Tree was a 75 foot Douglas fir grown on Weyerhaeuser Company’s Clemons Tree Farm in Washington State. The tree was shipped by rail to Washington, DC, where it was erected and displayed on the Ellipse. This film footage shows cutting of the tree in November 1961, and the ceremony at rail yard prior to shipment. Film is from the Weyerhaeuser Company Records held at the Forest History Society:…

The National Christmas Tree tradition stretches back to 1923 but in 1954 the decision was made to do something more extravagant and impactful to woo more tourists to the area and do something really special. The Pageant of Peace was born, a celebration of the holiday season that included music, art, and lights, with the centerpiece being what was being called “the National Community Christmas Tree”, culled from the great forests of America and erected on the National Mall where the Pageant and “Pathway of Peace” display would be located. There were national displays, international exhibits, participation from civic and religious organizations and all sorts of activities for children and adults alike. Over the years, the Pageant transformed and changed with the times. Some years it reflected a more somber national situation; in 1963, after the assignation of Pres. Kennedy, the lighting of the tree was delayed for several days to allow for a period of mourning and a more somber ceremony followed. Some years it was befallen by delays and problems. In 1970, the tree came from Nemo, South Dakota and along the way it derailed twice; once near Beemer, NE and again near Pittsburgh, PA. The tree was thankfully undamaged. The tree then laid over for a few days at the Army Map Agency siding near Dalecarlia Reservoir, apparently so the soldiers could keep souvenir-hunters away from stealing branches off the tree in Georgetown.

But at the center of each Pageant was the tree itself. A symbol of pride for whatever region it came from, there was often a good bit of pomp and circumstance at each end of its journey from forest to the National Mall. Ceremonies were held when the tree was cut, when it departed on rail car and when it arrived in Washington DC. Sometimes Santa or Mrs. Claus would make an appearance. And always, officials from the home town, suppliers, as well as the railroads that transported the tree would be present to get every P.R. dime out of the occasion. I dug around for a few hours and tried to gather all the info I could using newspaper clippings, photos and other articles online to figure out details of what years the tree traveled by rail, what route it took and what cars were involved. (I am a model railroader, after all.)

Here is a link to my spreadsheet, a work in progress.

From what I can gather, the tree traveling by railroad began in 1954 (from MI) and ended in 1972 (from WY). There were a few years in-between where the tree traveled by truck and not by rail. I also could not find definitive data for several years but the fact that the tree came from far away, one can assume it traveled by rail. In at least one of the years, the final leg of the Tree’s journey was on the PRR. I’m not sure if this was because the Pennsy wanted a piece of the P.R. pie or logistics. In 1973, after pressure from environmental groups, the committee decided to use a living tree. The same tree was used for several years until it was damaged and needed replacing. In 1977 a dead tree was again used, but in 1978 they went back to using a live tree. I stopped tracking in 1985, as that is when trains stopped running on the Georgetown Branch and at that point they were still using the living tree.

I am obviously most interested in the 1945-55 timeframe as that is the era I am modeling. In 1954 the tree came to DC from Michigan on two Soo Line flat cars. (more on this in a future article.) In 1955, the tree traveled from the Black Hills of South Dakota to Georgetown in a CB&Q 65’6″ 70 ton mill gon, likely class GM-3A or GM-3B. I do plan on modeling both of these trees for my layout, but I first need to find acceptable freight cars that fit the bill. The CB&Q mill gondola will be particularly challenging as I have yet to find a suitable HO scale model. Maybe I will have to build one! Well, that’s it for now. Hope everyone had a Merry Christmas and here’s to a Happy New Year!

Mill? Brewery? Dairy? Ice House? Gym? 3400 K St Historic Photo Tour

3400 K St., Google Maps, Dec 2021. Note how the three supports for the Whitehurst Freeway extend out and into the wall of the structure. This is where a 4-car siding was located on the Georgetown Branch.

Something that has been a bit of a conundrum for me over the years is what type of business, exactly, was located at 3400 K St during my modeling era, 1945-55 and what exactly the structure looked like. On the 1954 B&O Form 6 (which describes rail customers, siding lengths, freight agents, locations, etc.) it reads “Chestnut Farms-Chevy Chase Dairy”, 4-car length, milepost 10.4. The siding does not appear on the 1941 Form 6.

1954 B&O Form 6 excerpt
June 1963, B&O RR Track chart with proposed Potomac River Freeway shows the siding at 3400 K St.

Maps have varying names listed for the industry located at 3400 K St.:

  • 1888 Sanborn: vacant flour mill & coal house
  • 1903 Sanborn: Crystal Plate Ice Co. & vacant
  • 1919 B&O map: no name, just “2 Story Brick
  • 1921 Baist: American Ice House
  • 1928 Sanborn: Crystal Plate Ice Co.
  • 1954 B&O Form 6: Chestnut Farms-Chevy Chase Dairy
  • 1959 Sanborn: National Dairy Products Co.
  • 1963 B&O map: W.S. Brenizer and “Brewery” (I suspect it was The Guggenheim Co.)

I decided to go back through photos and maps I have in my files to see if I can get an idea of what type of structure existed at this spot over the years. I’m starting way back, long before the railroad came to town because I think the history and background is pretty special. The first image comes from the year the Civil War ended. Georgetown looked pretty different back then than it does now.

The waterfront in 1865. An image from the Georgetown Metropolitan website. I believe the 3400 block of K St is where that very large four-story warehouse is located, about a third of the way from the left. The Washington Aqueduct bridge is visible on the very far left side. Georgetown Univ. is also visible, top left.
Sept 28, 1886. Another view showing some waterfront detail. A few years after the previous photo and the “coal house” structure has a large sign painted on its end. DC Historic Society, Potomac Boat Club collection.

First map reference is a snip from an 1888 Sanborn Map. Note the 3400 K St. location is occupied by a Vacant Flour Mill and a Coal House, visible in the photos above. Also note the prominent overhead coal trestles which were used to transload coal from canal barges on the C&O Canal to ships docked on the Potomac River wharves.

(1888) Sanborn Fire Insurance Map from Washington, District of Columbia, District of Columbia. Sanborn Map Company. [Map] Retrieved from the Library of Congress,

And here is a detail from the above map:

1888 Sanborn Map, LoC.
View down K St, ca 1890. I believe the large mill building in the center occupied the 3400 K St. location. This is an excellent view of the overhead coal trestles. Note what looks like tracks visible in the pavement below. Image from Old Washington, D.C. in Early Photographs, 1846-1932, By: Robert Reed, 0486238695, 1980.

Here is a clip from a Sanborn Map from ca. 1903. Remember this pre-dates the arrival of the B&O (1910), but the Georgetown Barge Dock and Elevated Ry. Co. had been incorporated in 1889. 

(1903) Sanborn Fire Insurance Map from Washington, District of Columbia, District of Columbia. Sanborn Map Company, – 1916 Vol. 1. [Map] Retrieved from the Library of Congress,

The business is listed as Crystal Plate Ice Co. Within the warehouse are “Freezing Tanks” and “50 Ton Ice Machinery” and an attached “Cooling Shed.”

August 14, 1904. Note the presence of the tall coal trestles extending to the wharves. DC Historic Society, Potomac Boat Club collection.
August 14, 1904. Another nearly identical view from the same collection.
DC Historic Society, Potomac Boat Club collection.
A few years later, 3400 K St, ca 1911-18. HABS collection.
(1920) Key Bridge under const. United States Washington D.C. District of Columbia Washington D.C, 1920. [Photograph] Retrieved from the Library of Congress,
1921, “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
Note the “coal house” structure to the right has been razed. Ca. 1920s, “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
Aug, 1927, “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
Ca. 1920s. A view from the other direction. “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
1928 Sanborn Map.

A photo by Theodor Horydczak shows the site ca 1920s, likely the late 20s. Note that the building appears to have been either been razed, rebuilt or heavily renovated and the Key Bridge is now complete.

Horydczak, T., photographer. Lone Star Cement Co. Lone Star Cement Co. and negative of adjacent property. Washington D.C, None. ca. 1920-ca. 1950. [Photograph] Retrieved from the Library of Congress,
1931. “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
June, 1931. “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
July 1931, “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
July 1931, “Airscapes” of American and Foreign Areas, 1917 – 1964, National Archives
A view down K St. October 28, 1936, from the Barriger Collection.
Harris & Ewing, photographer. (1930) Train tracks near Potomac River, Washington, D.C. United States Washington D.C. District of Columbia Washington D.C, 1930. [April] [Photograph] Retrieved from the Library of Congress,

It appears that in the 1940s an addition was made on the east end of the block. I believe sections of the older structure (from the 1920s era) remain, but it seems that some of the structures were replaced.

Note the large “bottle” sign at the top right corner of the building, facing away from the photographer. A neat detail. If only I could see the front of it!
Oct 17, 1942, 3400 K St. – flooding. Credit: Acme Photo. eBay purchase, personal collection.
A promotional photo by Theodore Horydczak captured a portion of the “new” structure, with the bottle sign clearly visible. Horydczak, T., photographer. Potomac Electric Power Co. miscellaneous. Manhole crew and truck I. Washington D.C, None. ca. 1920-ca. 1950. [Photograph] Retrieved from the Library of Congress,

It is likely the structure was changed when the Whitehurst Freeway was being constructed, ca 1946:

1958 Sanborn Map. Note that the structure now reads “Built 1946”. I suspect that in the mid-40s, or perhaps when the Whitehurst was being built in 1947, the old structure was razed and a new on built in its place to accommodate the new freeway structure.
1948. Whitehurst Freeway construction showing the roof of the new 3400 K St. structure.
1948. Whitehurst Freeway construction showing the roof of the
new 3400 K St. structure.
1948. Whitehurst Freeway construction showing the roof of the
new 3400 K St. structure.
1948. Whitehurst Freeway construction showing the roof of the
new 3400 K St. structure.
1963, DDOT DC.
1972, Hurricane Agnes. DDOT DC.
1972, Hurricane Agnes. DDOT DC.
1991, DDOT DC
1991, DDOT DC
1991, DDOT DC
1991, DDOT DC
1997, DDOT DC
1997, DDOT DC

I hope you enjoyed this photo tour of the 3400 K St. location. I commuted from Bethesda to Rosslyn by bicycle for a few years and every morning and evening I walked up and down 34th St past this location from K St to the bridge over the C&O Canal and on up and over Key Bridge. Often I would ponder the history of the building and what came before. When I was commuting, it was a fitness center / gym and various professional offices. No doubt more research is in order to get more details on the businesses that operated here, but this is a good start. When I have more information, I will post an update.