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Main Line
Written May 1, 2008


Below, a towboat pushes barges up the Allegheny River in Pittsburgh.  I took the picture from the foot of Voeghtly Street on the North Side, looking across toward downtown's 11th Street.

An innovative bridge of stone and wood and iron once crossed the Allegheny at this spot.  Surprisingly, its purpose was to provide not a dry path for vehicles, but another waterway for boats!

Let's begin the story half a mile downstream, near PNC Park.  Off Federal Street, between Allegheny Center and the railroad tracks, there's a block-long parking lot.  I've drawn a green box around it on this Google Earth image.

The walls on either side are made of 20th-century concrete.  But somehow these walls remind me of stone, and the long straight lot reminds me of a 19th-century canal.

And I've come to believe that this piece of land was in fact once part of the Pennsylvania Canal.  As I gaze at the string of puddles . . .

. . . I imagine a ghostly canal boat from long ago, as in a painting by William McGrath.

In 1817, New York State started construction on the Erie Canal between the Hudson River and the Great Lakes.  Completed in 1825, this waterway was highly successful, carrying passengers and freight between Albany and Buffalo.

Pennsylvania decided it needed a canal of its own.  The next year, 1826, construction began on the Main Line of Public Works connecting Philadelphia to Pittsburgh.

Its completion in 1834 shortened the trip dramatically.  Passengers and goods could now be moved more than six times faster than before.  It used to take 23 days to cross the state by freight wagon.  On the Main Line, it now took only 3½ days.

But this Pennsylvania Canal became obsolete in 1854 when the new steam-powered Pennsylvania Railroad sped up the trip by another factor of six, reducing the time to 13 hours.  The railroad bought the canal and shut it down in 1857.

However, one thing bothered me about the canal in Pittsburgh.  Why did the route run along the North Shore?  There's a perfectly good river less than a quarter mile away.  Barges ply it even today.  Why would anybody build a canal parallel to a river?

Well, there were no diesel-powered towboats in the 19th century.  Considering the technology that was available, the canal made operations much easier.

A packet boat like this requires calm water.  The sides of the channel have to be steep, so that the boat can get close to the towpath and its motive power — a mule.  A canal can be built to these specifications, while a wild river would complicate operations with its currents, shoals, rapids, and shallow banks.

But the Main Line of Public Works was not merely a canal.  It actually began with a horse-drawn railroad, leading westward from Philadelphia, through the suburbs still known as the "Main Line," past Lancaster to Columbia on the Susquehanna River.  There the waterway began.  It had to be separate from the rivers, but it followed them closely by building on the level river banks.  The route followed first the Susquehanna River and then its tributary the Juniata to Hollidaysburg.


Then it was back to the rails for a 36-mile portage across the mountains.  The Allegheny Portage Railroad hauled the canal boats up and down the slopes on ten inclined planes, each with a stationary steam engine to power the ropes.  However, the ropes wore out, and sometimes they broke with disastrous results.  John Roebling, an immigrant from Germany now living near Pittsburgh, replaced them with iron cables, called "wire rope," made by hand on his Saxonburg farm.

Pennsylvania's canal resumed at Johnstown, following the Conemaugh River, which flows into the Kiskiminetas River.  From Freeport the waterway would follow the Allegheny River to Pittsburgh.  But on which side of the river should it be built?

At that time, the part of Pittsburgh north of the river was actually a separate municipality called Allegheny.  Residents of Allegheny wanted the canal to follow the north bank and end in their town; Pittsburgh residents wanted it to follow the south bank and end in Pittsburgh proper.  The state decided on the north bank, where the flood plain was broader.  But they agreed to branch the canal and built two terminals, one in each town.

An 1828 city map shows the western end of the canal, highlighted below in blue.  The northern branch through the borough of Allegheny presented few problems.  However, to reach Pittsburgh the southern branch had to cross over the river on a bridge, called an aqueduct, from Voeghtly Street to 11th Street.

At Liberty and Grant Streets (the red star), a historical marker says "The loading basin and western terminus ... was here."

To the northeast of that loading basin, notice the rows of warehouses — the beginnings of the Strip District.

The canal continued south, tunneling 810 feet through Grant's Hill before reaching the wharves along the Monongahela River, the gateway to the Ohio River and the West.

Here's the same blue line, overlaid on a view of the city 180 years later.

At the southern basin, the red star still marks the location of a transportation terminal — for buses and Amtrak.

It appears that the northern loading basin was near the present-day Clark Bar, and the waterway finally connected to the river near PNC Park's right field foul pole.

A quarter mile downstream from that foul pole, I've discovered that the final connection is recalled in the 21st-century water feature shown below, Canal Square.

The pool ends in a decorative waterfall leading down to the river.

Wait a minute.  Back up.  Canal boats crossed the river on a bridge?  You'd think that a canal boat could cross a river by just floating from the canal water into the river water on one side and back into the canal water on the other.

But the depth of the river varies with the seasons; therefore, locks would have been necessary on each end to raise and lower the craft between canal level and river level.

Also, remember that canal boats didn't operate well in rivers, so it was usually necessary to build a slackwater dam across the river to give them a current-free pool in which to navigate.  (Unfortunately, the dam then interfered with other river navigation, such as rafts of timber floating downstream.)  The mules were unhitched and loaded onto a ferry.  The boatsman would either trust his craft's momentum to carry him to the far shore, or propel the boat by pushing a long pole against the bottom, or grab a rope strung from shore to shore and pull the boat across.

All of these disruptions created a bottleneck that could slow a boat's passage by a day or two.  It was a much better idea to continue the canal uninterrupted on a bridge.  Pittsburgh's first such bridge was a covered wooden aqueduct, completed in 1829.

English novelist Charles Dickens and his wife used that aqueduct when traveling to Pittsburgh via canal boat in the spring of 1842.  In American Notes for General Circulation, he wrote that on Monday, March 28, “furnace fires and clanking hammers on the banks of the canal warned us that we approached the termination of this part of our journey.  After going through another dreamy place — a long aqueduct across the Alleghany River, which was ... a vast, low, wooden chamber full of water — we emerged upon that ugly confusion of backs of buildings and crazy galleries and stairs, which always abuts on water, whether it be river, sea, canal, or ditch: and were at Pittsburg.  Pittsburg is like Birmingham in England; at least its townspeople say so.  ... It certainly has a great quantity of smoke hanging about it, and is famous for its iron-works.”

Ulysses S. Grant wrote of taking the canal in the opposite direction, when travelling from Ohio to enroll at West Point in May 1839.  “From Pittsburg I chose passage by the canal to Harrisburg, rather than by the more expeditious stage.  This gave a better opportunity of enjoying the fine scenery of Westen Pennsylvania, and I had rather a dread of reaching my destination at all.  At the time the canal was much patronized by travellers, and, with the comfortable packets of the period, no mode of conveyance could be more pleasant when time was not an object.”  From Harrisburg to Philadelphia there was a railroad, the first Grant had ever seen.  “I thought the perfection of rapid transit had been reached.  We travelled at least 18 miles an hour when at full speed and made the whole distance averaging probably as much as 12 miles an hour.  This seemed like annihilating space.”

In 1844, the original aqueduct was destroyed by an ice jam.  Its replacement was designed by wire-rope pioneer John Roebling (right).  On his 1845 aqueduct, the trough that carried the canal water was 1,140 feet long, 15 feet wide, and 8½ feet deep.  Because it was suspended by cables from six piers, it was Roebling's first suspension bridge.

That bridge is long gone, but three years later Roebling built another (only half as long) over the Delaware River at Lackawaxen, PA.  It's still there.  I found this picture, in which you can just make out the reddish cables curving from the top of one pier, down to the bottom of the span, and up to the top of the next pier.

Roebling went on to build other suspension bridges, including one that still crosses the Ohio River at Cincinnati, before capping his career with the Brooklyn Bridge in New York.

There are still a few places you can visit to see traces of the Pennsylvania Canal, including the town of Saltsburg.  A list is at this website.  However, the only vestiges that I can locate in the Pittsburgh area are the names of certain streets, including some near my present residence.

Walking east from Federal Street and the parking lot (marked green above), we swerve slightly to the north and find that we're now on North Canal Street (blue).  Further east, beyond the ramps of the Veterans Bridge, we encounter South Canal Street (orange).  I suspect that North and South Canal got their names because they bordered the east-west waterway.

Five miles up the Allegheny, there are more clues in Sharpsburg (below).

This is another town that preserves traces of the route, bracketed between its own North Canal Street (blue) and South Canal Street (orange).  The latter is paralleled by Front Street (pink), a name that often denoted a waterfront dock area.

Canal boats drawn by mules appear on the borough seal (two versions at left).

And there's a Gran Canal Caffé on North Canal Street.  However, the restaurant's name was probably inspired more by its street address than by any memory of the waterway of long ago.



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