When B&O planned this right of way circa 1830, no one accurately knew the gripping ability of a steam locomotive's metal wheels upon metal rails. There were but a handful of primitive steam locomotives to be found anywhere at that time, and B&O didn't have an operating one to test.

So, B&O conquered the steep stretches up to and down from Mt. Airy by building inclined planes at relatively steep areas of terrain. Horses would assist in pulling trains uphill there, and plans were drawn to employ steam-powered winches. The planes proved to be a bottleneck so were bypassed in 1838 via the Mt. Airy Loop.

This aerial from 1938 shows that Planes 1 and 2 were still visible a century after their disuse. Portions have remained discernable into the 21st century, as seen below.

This driveway leading up from Twin Arch Road to a junkyard marks the location of B&O Plane 1, the first inclined plane encountered on the trip west.

As a result, B&O chief engineer Jonathan Knight's estimate of how steep a grade future locomotives could climb was little more than an educated guess, and that guess turned out to be quite conservative. Consequently, Plane 1 hardly looks formidable by today's standards.

The even grading, the angle, the unusual road surface, the cut, the proximity of commercial property (the junkyard) in an otherwise residential area all say a railroad had been here. The curve, however, is a puzzle. It is likely the planes were straight, or nearly straight, runs, so the I surmise the curve was added later, perhaps to facilitate room for a nearby house.

Quoting statistics from Harwood's Impossible Challenge book, Plane 1 was 2150 feet long, mostly through a shallow cut, and rose 80.4 feet. The grade was 3.7%. In 2004, this was the view west from partway up from Twin Arch Road. The ascent continues ahead along the north edge of a junkyard. The grade is no longer uniform along the full length, which means Plane 1's shallow cut has been filled in places. The deepest part of the cut had been near the middle of Plane 1.

Draft animals assisted pulling the trains up each plane, and were then walked back down the hill to stables.

Plane 1's cut is visible as a slightly shadowed area running right to left across the middle, just north of the junkyard cars.

The alignment progresses west (left) past the junkyard, past a quarry, heading for what had been a busy grade crossing with Frederick Turnpike. The base of Plane 2 is 3774 feet ahead.

Part of the alignment has been erased by the quarry, but resumes at its edge as seen here. It appears to now be a road to the quarry which is also a haven for ATV riders.

The railroad was determined to keep the sections between the planes as level as possible. At this location, a surprising amount of fill was employed to raise the ground.

Auto repair facilities and the AAA have appropriated and paved B&O's original route. Behind the photographer and slightly right, hidden by brush 230 feet away, are the remains of the Twin Arch Bridge seen below.

Twin Arch Road is named for the 1900-constructed Twin Arch bridge it passes under, but few people know there had been a previous Twin Arch bridge.

Near the end of what is now Ridgeville Boulevard East are the deteriorating remains of the first Twin Arch bridge. Beginning in 1830, the arches carried B&O over this Patapsco River tributary plus Frederick Turnpike, then Maryland's primary road to the midwest. Only one arch survives, having lost its twice-as-large, adjacent sibling many years ago to turnpike improvement.

Note the style of stonecutting and dressing of the arch stones as it will be seen in another arch below.

The little bridge saw railroad for only about eight years before B&O abandoned it in favor of the Mt. Airy Loop alignment. However, its cousin on the west side of the ridge has remained active.

Unobstructed views require the right timing since the arch is usually covered by greenery. The arch walls are about 10 feet apart at water level.

Many overhead wires still follow the former Frederick Turnpike. Construction of a new home (distant left) during 2023 blocked CSX's access to the OML via the ex-turnpike, so CSX put the Twin Arch back into service as a maintenance road. Over 180 years had elapsed since the surviving arch saw railroad use, a slumber duration that must be the world record among reactivated rail structures.

CSX did not modify the masonry, instead they merely cleared brush and layered fresh dirt on top, making the bright arc at right. That arc matches the curve of a stone arch now traversed by maintenance of way trucks. Jonathan Knight, B&O engineer in 1830, would be proud. What did you create today that will still be used during the 2200s?

The arch under which the turnpike had passed was gone by the time of this 1930 photo. The curve of the surviving arch can be glimpsed beyond and right of the diamond-shaped sign near photo center. The road in the foreground is Frederick Turnpike, the original route west from Baltimore to the National Road. Given how puddles form in this area even today, the area under the road arch was probably a muddy mess, impetus to remove its stones and elevate the turnpike soon after B&O abandoned the planes route around 1839.

The trains returned circa 1905 with the then-new Mt. Airy Cutoff route through Mt. Airy Tunnel. That brought a grade crossing with the turnpike, something B&O's Twin Arch had avoided during the 1830s. The surviving arch would prove handy for construction access to a grade elimination bridge project underway off photo left. The new road would be named US 40. A limited-access version of US 40 would bypass Mt. Airy during the 1950s, and be upgraded into Interstate 70 (blue line) circa 1970.

No automobiles are in view: the Great Depression reduced travel. Still, the route was popular enough to warrant a billboard, this one for Southern Hotel in Baltimore.

Links: full 1930 photo, turnpike mile marker, Southern Hotel (scroll down at site)

This is the much the same view as the prior after decades of tree growth and abandonment have crumbled the turnpike. Stagecoaches continued west onto the Hagerstown & Boonsboro Turnpike then the Cumberland Turnpike to connect to the National Road at Cumberland, Maryland. The National Road was the first improved road paid for by the US Federal Government.

A National Road to the west was promoted by Congress in 1806 while Thomas Jefferson was President. Construction did not begin until 1815, and it was not until the 1850s that the road reached St. Louis.

The portion of the turnpike here consists of a macadam center surrounded by strips of concrete. The National Road was the first in the US to employ macadam, the surface named for its inventor John Loudon McAdam.

Link: National Road (wikipedia)

Where did the Twin Arch's second arch go? It probably has been here all along, merely rotated 90 degrees to elevate Frederick Turnpike over a creek and out of the mud. I believe that is the case because the voussoirs (arch stones) exhibit the same finishing style as found in the surviving Twin Arch and only one other B&O bridge. Note also the presence of irregular, smaller pieces within the arch, something B&O never included. It may have been a non-railroad crew that modified B&O's bridge into the form and location seen here.

This style of arch stone is found at only one other place, the contemporaneous B&O bridge near Mill Bottom Road on the west side of the ridge.

This is the view west southwest from the surviving arch which, prior to reactivation, was overgrown with brush and dissed by trash. The pink line designates Frederick Turnpike's remains. The repurposed second arch is located to the right of the thick utility pole.

Looking back, the arch is hidden in the brush at the left edge of this photo, snapped at a location I dub the "Crossroads of Mt. Airy".

For over 200 years, this spot on the east side of the ridge has been a key for mid-atlantic access to the west. Initially, the Frederick Turnpike (pink) forged through, followed by B&O (green) in 1831. Bits of turnpike pavement can still be seen as of 2023 to the south (right) of the tracks along the pink line.

B&O abandoned the green alignment by 1839, but in 1901 returned adjacent with the Mt. Airy Cutoff, which are these still-active tracks. The railroad's grade crossing with the Frederick Turnpike was eliminated with the 1930s construction of an overpass in distance (red). The red route was renamed US 40 until the mid-1970s when Interstate 70 (blue) obviated it. Now US 40 and I-70 share the blue route.

This is the view opposite that of the prior picture. B&O's original alignment (green, bottom left) heads toward I-70 which is behind the trees on the left. According to my calculations, the base of Plane 2 is now buried under I-70 or possibly even on the other (south) side of the interstate. How did I estimate its location and path? See below.

My Plane 2 location estimates are based on the following two simple assumptions: 1) the planes were straight, and 2) the data Harwood published regarding the length and height of the planes is accurate. With that information, finding just a few plane endpoints lets us extrapolate the others.

I have found confirming evidence of Plane 3; it will be pictured on the next page of this tour. According to Harwood, Plane 2 met Plane 3 at the top of the ridge, separated from each other by 600 feet. Plane 2 was 3000 feet in length and rose 99.6 feet from a base elevation of 728 feet.

The next step is to examine topographic maps that predate I-70 and see if a line can be sketched to match that data. Pictured here is a small clip from a 1909 USGS topo map. The tracks extending across the middle are B&O's then-new Mt. Airy Cutoff. The blue line I've added represents I-70 today. The green line designates Plane 2, and extends about 3000 feet from an elevation of about 725 feet up to one about 825 feet, a grade of 3.3%.

Notice how the left (west) end of the green line parallels a minor road or path, likely the remains of Plane 2. At its right end, another minor road or path follows B&O's original alignment to the base of Plane 2. At that location, the small black box represents a structure that might very well have been stables for the horses that worked the plane.

B&O considered steam powered winches and cabling to lift the trains, and may have begun constructing such at Plane 3 where the grade was 5%. That technology was subsequently used at other, steeper locations a century later. The Sant Joan Funicular at Monserrat mountain in Spain climbs a grade in excess of 65%. Ninety degrees would be straight up, like an elevator. Funicular railcars are, by definition, permanently attached to a moving cable.

CSX trackwork during the autumn of 2013 called my attention to this cut in a hillside (mound behind the green line) which I believe is a Plane 2 remnant. Per the old map, it is in the right spot and at the proper angle.

The cut follows the south bank of a small stream that flows toward and under the twin arch. B&O liked following such streams, and indeed the lack of trees along the bank here may be an artifact of the route to the base of Plane 2. At upper left behind brush note a road sign along I-70.

That sign is at right in this view. The green line indicates how Plane 2 might have been positioned relative to I-70 today. Bulldozers have mounded the soil so that I-70 sits at a higher elevation than B&O's original alignment. Said another way, that alignment is now buried deep below the asphalt somewhere in this vicinity.

After many careful measurements and much study, I am confident the base of Plane 2 had been near the black car in this photo. Notice how even today that is a low spot of the highway. In the distance are road signs for the Mount Airy exit. Unseen behind trees on the right are the Mt. Airy Cutoff tracks.

The Mt. Airy cutoff, lower in elevation than what had been Plane 2, dug under that original alignment roughly as envisioned here. In the distance, Plane 2 had marked the edge of an auto junkyard that was redeveloped into the Peacock Shopping Center just a few years before I began scouting the planes.

According to my measurements, the back edge of the Peacock Shopping Center erased any Plane 2 remnants here. This is the view from the loading dock area behind the stores.

As if to intentionally throw us off, the utility pole line seen here follows a hillside shelf up toward the ridge; it sure smells like railroad, but I'm convinced it's not Plane 2.

Why not? There are two reasons. First, on the other side of the ridge, there is a similar utility pole line that definitely does not mark Plane 3. Second, aerial photos that predate the shopping center show the Mt. Airy Cutoff tracks, the pole line, AND an old "scar" in the landscape that forms a straight line and is in the proper location. I believe that scar is Plane 2.

Judge for yourself. In this aerial photo that pre-dates the shopping center, I-70 runs east west and is marked by blue. Roughly parallel and north of (above) I-70 are the Mt. Airy Cutoff tracks. The next parallel line, traced by dark red, is the utility pole line; note the slight curve, Plane 2 would not have had such a curve. Above that is another parallel line (bright green) that would appear to be a road within what was at the time Delauder's Junkyard. That's Plane 2.

Basically the same location as prior photo, now looking the opposite direction.

The dark area in the lower-left corner is the maw of Mt. Airy Tunnel's east portal.

With Google Earth as guidance, the green line marks where Plane 2 had been relative to the loading dock behind the shopping center. Note how the line is parallel to the concrete slab, which is parallel to the back of the building, which is parallel to the edge of the lot, which is likely parallel to what had been Plane 2.

The pole line of the prior two photos is behind the guardrail seen in the distance on the right.

The top of Parrs Ridge is seen in the distance; this was the final stretch of Plane 2.

B&O planned to use steam winches to assist lifting the trains up each plane, but historical records are unclear if steam ever replaced the horses. There are reports of the winch system components being ordered, then later sold off, and an account that sounds like it describes a steam lifting mechanism, but little else. A definite answer may have been lost to history.

The white striped lane in the foreground is the exit ramp from westbound I-70 to northbound MD 27.

Plane 2 topped out right about here. The green line's distant endpoint is the location from which the prior photo was snapped.

The utility pole line re-emerges from underground. The pole line very closely follows the route of the Mt. Airy Tunnel.

I'm standing on the top of the ridge aside the aptly named Ridge Road that marks the border between Carroll and Frederick Counties.

According to data published by Harwood, the alignment pierced the ridge here within a 600-foot long man-made cut. The cut began roughly at the distant endpoint of the green line. Ridge Road was carried over via a wooden bridge. Both the cut and the bridge are long gone, but this was their location.

Back on the Carroll County side of Ridge Road, here's the view west toward the shooting location of the prior photo.

Just beyond the brush in the distance, a dirt road clearly defines Plane 3, the subject of the next tour page.

CSX has taken advantage of the high spot by installing a communications antenna, the dual spired pole on the other side of Ridge Road. It probably makes a great lightning rod.

Trick or treat! This photo, snapped on Halloween, at first tricked me into thinking I had found Plane 3. Only after further research did I determine the utility pole line basically follows the Mt. Airy Tunnel which is deep underground here. Plane 3 is actually adjacent on the left; new houses are going up on the right.

Next to (behind) the shiny new communications box is this older structure. My speculation is it tops a ventilation shaft for Mt. Airy Tunnel.