've been running — and walking — in Highbridge Park literally for years. I recall back sometime in the late 1960s or early '70s, walking with a couple of friends from work the length of the Old Croton Aqueduct (aka the "OCA") from Croton to New York and having to stop at the Bronx end of the High Bridge, which even then was fenced off. We somehow found our way back to the Washington Bridge, crossed over to Manhattan and eventually found the OCA again down the stairs from the High Bridge Tower.
As for running, I recall running along the OCA with Susan and finding a path up from the end of the High Bridge to Amsterdam Avenue. Eventually we discovered the ornate staircase on Laurel Hill Terrace which led down to a park road which took us all the way to the north end of the park. This was our original "High Road". This route was featured in my 2011 report , one of our better runs.
The "Low Road" became one of our regular routes at least as far back as 2007, when we discovered the way down along the Harlem River Drive entrance ramp at 155th Street, and thence to the promenade. This was a great alternative with no hills! And it also led to our discover of , aka "Swindler's Cove".
As for the "Mid Road" (western sidewalk of Harlem River Drive) I recall trying to find a way to walk around Manhattan sometime in the '70s or '80s (clockwise) and when I got to Highbridge Park, I started south along the sidewalk of the Harlem River Drive at the base of the cliffs, but eventually had to give up and make my way to the top through the maze of highways which cross the park right at its mid section. Then 6 or 7 years ago, Susan and I replicated this exploration, but reaching a dead end, we scrambled up the rock face to the High Bridge's Manhattan terminus.
he very name "Highbridge Park" speaks of history. The construction of the Croton Aqueduct by the City of New York took place from 1839 to 1848, and getting the water across the Harlem River was one of the biggest problems. The high arched Aqueduct Bridge was the solution. From the day it was finished, the bridge became iconic — not only functional but beautiful. The series of high arches were reminiscent of ancient Roman aqueducts. It was called "the High Bridge" for obvious reasons and the park (first established in 1867) became "Highbridge Park". The picture on the right from the 1870s, shows an artist's rendering of the High Bridge, the tower, reservoir and pump house before anything else was built and with both shorelines as yet unspoiled.
The history of the park continued to revolve around Aqueducts, Bridges and Cars (or horse drawn Carriages). Consider these major public works projects which crossed over, under or through Highbridge Park:
Incidentally, the four rotating title pictures at the top of this report portray the four major projects to cross the park by the end of the 19th century: 1) The (Old) Croton Aqueduct, incuding High Bridge, the tower and pumping station, 2) Washington Bridge, 3) the New Croton Aqueduct, particularly Shaft 25 and 4) The Harlem River Speedway.
That photo of Washington Bridge with the boaters is a gem. Here's a full sized version . And don't you love the original caption for the speedway photo: "Is four miles long, was four years building and cost $4,000,000. Through East Dyckman Street connection is made with Riverside Drive, forming a pleasure-drive unsurpassed in the world."
our ability to navigate these routes and your enjoyment thereof will be enhanced by a little study before plunging straight in. First are the maps. Each of the three routes has a map along the left side of the text. Look at each route and see where it starts and ends and where the path changes direction. Look for detours or possible alternate routes. Then read the text.
The text is greatly enhanced by the slide shows. The main one for each route is brought up by clicking the "cover" picture for that route. In fact the slide show IS the route — the text merely explains a few things. The detour and various alternate routes also have their own slide shows.
So here goes ... enjoy! Then go out and run one of the routes. Even better, run all three!
or years running through Highbrdge Park meant running along the OCA. Period. When we got to High Bridge we would take the path (our "bushwhack") or the stairs up to Amsterdam, and then run along this thoroughfare to the north end of the Park. We would stay on Amsterdam past all the highway bridges, past Yeshiva University and and not even see the park till 188th Street, where we would run along the park for a few blocks. And that was it.
Then one day in June of 2011 when Susan and I were doing this run, we decided to at least stay on the sidewalk above the park instead of running up Amsterdam Avenue by Yeshiva University, so we took a right just past Washington Bridge on Laurel Hill Terrace. The first thing we found, beside some beautiful views and the fact that Washington Bridge has a nice sidewalk for crossing to the Bronx, was a wonderful stairway down into the park. "Wow, look at that, where does that go?" We didn't go down that time, but later that week I took a trip up there and did some exploring.
Well, I discovered a park road, very well maintained but seldom used by anyone, that went all the way up to the north end of the park. On our next run up there we took the road and it became part of our regular Highbridge Park run. I call this the north road and on it you get to see the loveliest and wildest part of the park on a gently rolling road with amazing views — and we never knew it.
Much later, in fact this summer, when I did the "Mid Road" and did some exploring in the middle of the park where all the highways cross, I went up through the arch in the Shaft 25 retaining wall and discovered 1) they are building a skateboard arena right in the middle of the highways and 2) there looked like there was a way up to Amsterdam Avenue just south of all the highways (just past the High Bridge Tower).
Then I discovered that you could link up this path to the top with our "bushwhack" (which at that time we has been unable to do for a couple of years due to construction on High Bridge). Thus the missing link was at last discovered and you can now do the entire High Road without setting foot outside the park!
The slide show gives a pretty good description of how to get through this mid section, but in very brief: 1) take the path (or for now, take the detour) up from High Bridge, 2) go north (to the right) when you get out of the woods into the field after the bushwhack, 3) go down the stairs when you reach the red brick wall (the detour rejoins the route at this point), 4) thread your way around the skateboard arena, 5) find the path near the top of the Shaft 25 retaining wall into the woods, and lastly, 6) head on this path towards Washington Bridge and loop around down through the arch and up the other side. Now you are on the north road, just before the Laurel Hill Stairway.
Voilà! You've made it. Need a guide? Talk to me.
Detour: The slide show gives the full route, but after the construction and renovation of the High Bridge, I found that the "bushwhack" is more difficult to follow. So you may want to consider the alternate route even though the bushwhack is still a possibility. It's shown on the map and it's no big deal, take the stairs up to the top, swing around the swimming pool and rec. center, and go right (north) 2 blocks on Amsterdam. Then take a right on the road opposite 175th Street, stay on the sidewalk down and to the left. When you get to the fence, go down the stairs and you'll be back on the main route. Here's a slideshow just for the detour: .
Alternate Route: There's also an alternate route (shown on the map at the north end) — it goes up to Amsterdam Avenue and ends up on the top of the hill. The regular route goes down the hill and ends on Dyckman Street. If you're headed to the Cloisters you might prefer the upper route. If you're headed to Inwood or the Bronx the lower would be better. Here's the slide show:
he "Mid Road" is a made up name, since it lies between the high and the low. Most of the time it's just on the other side of the Harlem River Drive from the Low Road (which follows the promenade along the river), but it has a very interesting path in the mid section. I did this route north to south when I was putting this report together, but there's nothing special about that direction.
It turns out the New Croton Aqueduct, which went through the park in the late 19th century has a lot to do with the middle section of this route. It seems that in 1896, a landslide occured when the Harlem River Speedway construction crew did some blasting on the cliff face just south of the Washington Bridge. The full story is related below, but the short of it was that some of the New Croton Aqueduct infrastructure was damaged, and so they had to build a retaining wall along the middle section of the Speedway, and the sidewalk (our "Mid Road") was put up on top of this retaining wall (which was between 10 and 16 feet high). For us, this was a big plus! Furthermore, where the slide occured, they built a structure to protect some equipment below. This is the Shaft 25 arched retaining wall and you get to it right after you pass through the great stone arch of the Washington Bridge.
When you get to this structure, the normal route is to go on by it and down the stairs (which appear to never be used) and make your way south along the narrow sidewalk — now at grade level — and continue south to High Bridge along the road. The sidewalk here has been obliterated by a dirt road used for construction, but hopefully in the future it will look a lot better.
At High Bridge there's a bit of a narrow section and then an overgrown section (see below), but basically you can continue on south with no trouble. The slideshow above will give a good feel for the entire route.
There's an alternative right in the middle of this route. Just south of the Washington Bridge arch, you pass by a stone structure with an arch in the center. This is the New Croton Aqueduct's Shaft 25 retaining wall (see below). Instead of going down the overgrown stairs to the Drive sidewalk, go up the stairs through the arch. At the top, find your way over and down to the left, underneath the Alexander Hamilton Bridge. Get on the well maintained park road which will take you to the bottom where you can rejoin the main route. This alternate will give you a chance to see the middle of the park with its myriad of highways, overpasses, exit ramps, entrance ramps and assorted mayhem. The alternate route is shown on the map. Here's a slideshow just for this portion:
Once you get to High Bridge, either along the highway or by using the alternate route, go under the foot of the bridge on the narrow sidewalk (beware of construction litter) and keep going under the viaduct (more on this below) and then fight off the overgrown bushes which make the sidewalk about 12 inches wide. Some folks have been known to think there is no sidewalk here at all!
Once in the clear, it's a straight shot all the way to 155th Street with the last portion up along side the entrance ramp.
There's a nice surprise when you get near the end, a little ways from the top of the ramp that leads to 155th Street. It seems that in 1913 (yes, 101 years ago) the New York Giants (the baseball team) built a stairway down the rocky slope so Washingtoon Heights residents could take a short cut to the Polo Grounds (), the Giants' home field . They named it after John T. Brush, their owner who had recently died. The Parks Department just rebuilt it and made a lovely little picnic area at the bottom. I explored the area and took the stairs up to Coogan's Bluff (huh? See ). And if you follow the slides show, you can too! Here it is: You'll end up on Edgecombe Avenue, a couple of blocks up from 155th Street. I think you will agree that this side trip is more interesting and attractive than those last 3 blocks up the hill on the main route.
did this run with Melissa in June of this year as part of a longer run and most of the pictures in the slide show are from that run. To get to Highbridge park, we took the Willis Avenue Bridge across to the Bronx, through a couple of parks, past Yankee Stadium and it was all pleasant going. When we crossed back into Manhattan at 155th Street, we decided take the low road since the last time we did this run, we took the high road. You'll see at the end of the section below (the "Shaft 25 Retaining Wall") how lucky we were to take this route on this particular day.
This route is probably the easiest, and it has beautiful up-close views of the river. When we did it, late spring flowers were out and the whole thing was very, very green. But do watch out for the occasional Poison Ivy. I have almost always done it south to north, usually on the way to the Bronx (such as Wave Hill or Van Cortlandt Park) or the more northerly parts of Manhattan (such as the Cloisters or Inwood Hill Park). Except for the down-ramp from 155th Street (which, of course is an up-ramp if you go the other way), it's as flat as a pancake.
If you've never done this route, here's how to get started. From the corner of Edgecombe and 155th Street, cross to the east side of the ramp that heads down to the Harlem River Drive. This is the downhill side and it's right where the sidewalk on the bridge to the Bronx begins. The picture on the left shows the spot. Click on the photo for a larger version. Stay on the sidewalk — leave the bike lanes for the bikes.
Proceed down the hill till you see the start of the ramp in the center of the road which gets you over the Drive to the shoreline. Cross on the crossing to the pedestrian walkway which is on the side of this overpass. See the picture on the right. Follow this all the way over, around and down and you'll soon be on the Harlem River Promenade.
The photos I took show the entire route including the above-mentioned down-ramp from 155th Street, and the straight shot along Dyckman Street over to Nagle Avenue. Make a note of photos #10 and #11 which show water gushing out into the Harlem River. This was quite a mystery to us since it looked perfectly clean and couldn't well be just run-off. Curiously, on the other side of the road (see photo #12), we noticed a structure on the side of the cliff which I had seen quite a few times and I thought I knew what it was — but it turns out I didn't. So what's going on? See below where it's all explained.
Of the three routes, this one is the most straightforward. Once you're on the river, there are no turns, detours or alternate routes.
There is one side trip just before you get to Dyckman Street that you really ought to check: , aka Swindler's Cove (see the map).
This is a pet project of the , a terrific group which has "adopted" a number of neglected northern Manhattan and Bronx parks. Sort of like the Central Park Conservancy for 5 parks and little or no budget! For some background, see .
This little enclave includes a boat dock, some wetlands and lots of natural areas packed into a small space. It also has some bathrooms and a community garden. An amazing and lovely oasis, well worth 15 minutes of your time.
n the course of this report, I mention "bumping into" this or that structure that was originally built in the past, sometimes the long past. Although you, the runner, can ignore these with a brusk "whatever!", some of you may want to know a little more about what these things are and what they're doing in a park. Of the list I drew up at the top of this report giving dates for major public works projects, let me single out two of them for a bit of study: the 1890s Shaft 25 retaining wall (part of the New Croton Aqueduct), and the 1940s arched viaduct (part of the Harlem River Drive project).
See that stone structure in the picture. Ever notice it? Here's a hint: this shot was taken from the far side of the Harlem River Drive and it's just north of the Alexander Hamilton (I-95) Bridge which is in the left corner of the picture. You might have been running along the river promenade or driving along the Drive on your way to points north. Or you might have gotten a glimpse of it if you were driving on the Deegan on the Bronx side of the river and happened to look in this direction.
I always wondered what it was and where that arch went. When I read somewhere that there once were a pair of tunnels built in the 1940s that went across Manhattan to take traffic to and from the George Washington Bridge, I though this must be the end of one of the tunnels. Notwithstanding the difficulty of getting traffic to and from this point, that idea stayed in my mind for years. But I eventually (with the help of Google) found out just exactly where in Highbridge Park those tunnels ended (see below) — and it is not here! Years ago on a run with Susan we went right by the front of this thing and I recall that 1) the back of the arch was just a stone wall — the arch didn't seem to lead anywhere, and 2) there was a sealed door of some sort on the right side of the archway which might have shown me what was inside, but that was as close as I got. So we ended up scrambling up the cliff face near the High Bridge — but that's another story!
Well, I found out what this thing is and what it's doing here. Our part of the story began when Melissa and I were running along the river this June (see ) opposite this thing and noticed a large gushing of water — very clean water — that was flowing into the river from some sort of pipe down at the water level. Melissa said "Maybe the water outflow has something to do with that thing over there". That was the trigger, and some extensive Google sleuthing got me to the answer. The pictures on the left help tell the story.
The picture of the water gushing out (below left) is actually a series of shots. You click on a picture to move to the next one in the sequence. Click past the 2 photos of the water gushing and you'll see a little diagram. It's taken from the report published by the Aqueduct Commision detailing the construction of the New Croton Aqueduct (1887-1905). It shows a cross section of the river and to the left, two shafts going straight down. These were built to let the workers get down to work on the aqueduct. The shaft closest to the river is "Shaft 25". It was the largest shaft on the aqueduct, being 16½ x 33 feet in cross section, and It went down 426½ feet below ground and was excavated in 1885-1887. This was pretty tough work where the main tools were pick and shovel and dynamite and it took many men working two 12 hour shifts a day for years to get it done. Here's a contemporary photo of Shaft 25 under construction: . At the top of the shaft a building called the "head house" () was constructed where pumps and valves and other equipment for the system was housed. Notice that at the water level there is a horizontal shaft from the river that goes back to shaft 25. It's called a "blow-off" and it's vital to the operation of the system. The blow-off allows excess water to be dumped from the aqueduct (under pressure) into the river.
The next two pictures show renderings of what this system looked like in the late 1880s. The building on top is the head house, the little archway provided access to the blow-out pipes and valves and the pipe outlets at water level let out the water, and it was evidently working by the early 1890s.
But just about that time, some Robert Moses of the day decided a roadway should be built along the shore using rock from the cliffs for a foundation. What's the harm from a little dynamite? And it was not just a roadway, but it was dedicated to horse racing by the city's elite. Thus was born the Harlem River Speedway. Then on January 27th, 1897, the whole rock wall in front of Shaft 25 came tumbling down when the roadway construction crew was doing some blasting near Shaft 25. As you might expect, this did not amuse the Aqueduct Commission, not least because Shaft 25 was one of the most critical points along the entire aqueduct.
So it was back to the drawing boards. Three things were done: 1) the blow-off pipes had to be extended across the Speedway to the new shoreline. 2) a retaining wall had to be built to forestall any future slides and to protect the roadway at the base of the cliff. The sidewalk had to run atop this retaining wall, and 3) Another retaining wall was built to protect the blow-off vault (which was now behind lower retaining wall) from rocks tumbling down from above and to stabilize the upper part of the rock face to protect the shaft itself. The arch in the center stood over the blow out vault and stairs rising to the upper levels were embedded in the right abutment of the arch and another stairway led down to the blow-out vault below from the left abutment (now bricked over). Here's a page from the 1905 report to the Aqueduct Commissioners explaining the whole thing (). They seem to have left out all the yelling and screaming that must have occurred.
The next picture, from 1905, shows the finished layout after all these jobs were done. So there is no tunnel or hidden chamber behind that arch, just the crumbly rock face, and behind the door we found years ago was just a stairway (above, right) to the upper regions that for some reason was off limits that day.
Today the head house is gone (lost in the building the Alexander Hamilton Bridge) and access to the shaft is made by removing some concrete slabs where the head house once stood. The arched retaining wall with the winding stairs still protects the blow-off vault, but is otherwise left for us runners and walkers to wonder about. The final 3 pictures show the state of these structures through the years to the present. And it's ironic that building a roadway led to the initial problems, and building 20th century roadways have changed this whole area so the original Aqueduct Commissioners would hardly recognize it. Just check out this 1951 photo () to see what the 20th century Robert Moses can do to what was once a wild and beautiful place! "Our" head house and arched retaining wall are fearfully huddling in the lower right of this wasteland.
But every so often, the water supply people need to flush this 120+ year old aqueduct, and thus on one Saturday morning in June, some workers, unseen by us, went into the old blow-off vault, turned some valves, at let the water flow. And only Melissa and I knew.
In the last paragraph above I speculated "every so often, the water supply people need to flush this 120+ year old aqueduct". It turns out I found that the recent period, about the last 10 years, is a special time for the New Croton Aqueduct. The entire aqueduct has been shut down while a filtration plant has been constructed in the Bronx. And part of the procedure to get it back into operation once the plant is completed, is to clean the entire aqueduct. Workers went down to the underground shaft and built the tunnels required to move the water to the new plant and then back to connect to the distribution system. Much of the work took place between the Jerome Park Reservoir, the new filtration plant about a mile to the north.
So on April 25th, Terry and I (see ) saw another instance of this water gushing out into the river. Either they do it all the time, or I have a knack of being there exactly the right times!
Shaft 25 comes into this picture because only from this structure can the entire aqueduct be drained since the bottom of the shaft is the lowest point on the entire aqueduct. The Shaft 25 blow-off valves and pipes, which we saw in action, are crucial to this operation. The plan, which I found , spells out procedures for "dewatering" and "rewatering" the aqueduct. And they don't just dump the water in the river. They check the chlorine concentration and the presence of dangerous microbes in the outflow. Ironically, they are protecting the river from our drinking water! Anyway, it's an interesting document, and if any of this interests you, give it a read. The dewatering and rewatering business is just a page or two starting at page 4.
What Melissa saw last June and Terry and I saw again this April were steps in the process of "dewatering" and "rewatering" the aqueduct.
To complete the story, I read in the May 8th NY Times
and a press release from the City
() that on May 8th,
the 120 year old New Croton Aqueduct went back into operation after about 10 years of work.
The so-called "Arched Viaduct" was built in the 1940s when the Harlem River Speedway — basically a scenic drive on the order of Riverside Drive — was being converted to the Harlem River Drive, a limited access highway. At the south end, the Drive was extended from 155th Street all the way down to 125th Street where it connected to the FDR Drive. To the north it went all the way to Dyckman Street — using most of the old Harlem River Speedway intact, including the long ramp down from 155th Street.
But the most disruptive feature, as far as Highbridge Park in concerned, was a long sinuous viaduct which carried 4 lanes of traffic up from the Drive to Amsterdam Avenue where it provided access to the 178th Street and 179th Street tunnels which took traffic across Manhattan to the GW Bridge (yes, and unbelievably, the tunnels are still there! See and for shots of the tunnel portals today).
Its structure consists of a series of brick faced arches, very distinctive, and unlike almost any modern highway construction. It almost looks like a giant Roman aqueduct, except it goes up hill! My best guess is that the engineers and architects were trying to emulate the look of High Bridge, which crossed the River on a series of arches.
The lower end of this viaduct starts right at the base of High Bridge and in fact the viaduct goes right through the westernmost arch of the bridge. Suffice it to say that it does NOT enhance the beauty of the bridge or the park.
Look at the picture on the right. It shows largely bare ground north of the High Bridge with the viaduct snaking its way up to the right. The Alexander Hamilton Bridge was still 10 years in the future. Click on the picture. This is the same scene in 1900. Besides the viaduct, the big differences are 1) High Bridge has all of its arches (the 5 arches over the river were replaced in 1928 by a steel arch span and 2) THE TREES! What happened to the trees in 1952? I hate to say it, but that whole area was cleared for the construction project (more like destruction project) that included the arched viaduct and the various connecting roads to the tunnels and to the Washington Bridge. I found this aerial taken in June of 1951 (). It shows a huge construction project which stretches across almost the whole park between High Bridge and Washington Bridge.
It's interesting to note that the viaduct first went up just to the 178th St. tunnel which was the only one there for 10 years. You can actually see traffic on that section in the picture. That original section of the viaduct was eventually demolished to be replaced by the more elaborate system under construction in 1951. You can see the stub of it in modern pictures, such as on Google Earth (). And here's a rare 1947 aerial picture showing the other end of the 1940 tunnel at the Manhattan end of the George Washington Bridge (: enlarge the photo and look at the far end of the bridge). It shows the center two lanes heading underground at what looks like Fort Washington Avenue. Remember, from 1940 to 1950 this tunnel accommodated 2 way traffic. And if you look closely, you can see High Bridge and the arched viaduct in the distance to the east.
When the other tunnel (179th St.) was completed in 1950, additional access roads were built as shown in that 1951 construction picture. One complication was that the tunnels were now one way (178th Street eastbound and 179th Street westbound). See () for an annotated version of the picture. Robert Moses must have been jumping with delight! And, as we know, it didn't end there. Within a decade, the Trans-Manhattan Expressway and the Alexander Hamilton Bridge were under construction. Its access roads, which sprawl like the snakes of on both sides of the river, further despoiled the park. But I digress, this is not about that.
About a week ago, I came upon a photo while I was using Google image search to find some images depicting the Harlem River Speedway. Ironically, it was misidentified as being a photo of the speedway — instead it was a photo of the Arched Viaduct which rises from the Harlem River Drive (formerly the Speedway) up to Amsterdam Avenue where it connects to various tunnels, bridge approaches, etc. etc. as you've seen in the previous section. Going back almost a year to when I originally wrote this post, there was one aerial view that bothered me. It was the one showing the George Washington Bridge in 1947 and at the highest magnification it showed where the 178th and 179th street tunnels connected to the Manhattan end of the bridge (See the photo on the left.). It was an excellent photo of a time long before the bus terminal, the Trans-Manhattan Expressway, the Alexander Hamilton (I-95) Bridge or the GWB lower level were built. In the distance you could just see the two bridges crossing to the Bronx and you could even see the Arched Viaduct connecting to 178th street. The problem was it also showed an extension of the viaduct connecting further up, perhaps to 179th, which extensions I had not thought were built till the early 1950s (see all the 1950 aerial views above showing this construction). It made no sense to me that they would build this in anticipation of the completion of the 179th Street tunnel, if they were just going to tear it apart in 1951, as evidenced by the many pictures I had found of that mayhem.
I looked a little more through the NY State archive of aerial pictures of all parts of the city and I found two more showing what the 1947 GWB photo showed. Click the photo on the left and you'll see what I found. The next three show the multiple arms of the viaduct in more detail, but the fifth picture was a game changer! It shows a perfect picture of the viaduct in all it's glory and it was taken in 1940! In no uncertain terms we can see the "Prongs" of the viaduct connecting up to Amsterdam Avenue at 175th Street, to both east-bound and west-bound traffic from the 178th Street tunnel, and the last extension to 179th Street (probably to Amsterdam Avenue since at that point the 179th Street tunnel was not finished). C/icking through several more photos, you can see a 1950 aerial of the area and finally a 1951 aerial, like the ones above in the previous section.
We need a new timetable. Here's my best guess:
Meanwhile the middle third of Highbridge Park is obliterated for over 20 years, and even now, 60 years later you see more highways than trees in this section.
One fine day, considering that getting around the base of High Bridge was perhaps the narrowest spot on the Mid Road and puts the runner closer to moving traffic than at any other spot, I thought if you could get in under the viaduct on one side of this bottleneck, follow along underneath, and then come out at the other side of the bottleneck where the road has a more reasonable sidewalk, then that would be a great help for the runner or walker. That's what this is about.
Why is it secret? Because the area is sort-of out-of-bounds (you have to go through a hole in a fence), a bit dicey, although not so much as if I suggested you climb up the cliff face — something I did once with my friend Susan — and it doesn't completely solve the problem. But it's fun and no one else in the world would ever think of doing it.
In short, look at the slide show and you'll see the route. You get in from the road which follows along next to the viaduct, the so-called Mid Road alternate route. Next, just go along as shown in the slide show and you'll come out onto the sidewalk. (At least I hope you make it out.) You've gotten around the narrowest part, but you still have to go under the viaduct (on a wide sidewalk, thank goodness) and fight the person-eating overgrown vines just beyond.
So you're on your own on this one, and be sure you destroy all copies of this secret account . .