Tower 1 - A History

Tower 1 @ South Station Terminal

When South Station was designed & built back in 1897 the purpose of the terminal was to consolidate 5 different railroads with their traffic, into 1 single facility. To do this required an enormous amount of planning & engineering that needs to take railroad traffic from 10 individual approach tracks and guide them to any one of the 28 station platforms safely & quickly. To accomplish this task, great care was taken to design the station's interlocking plant to be able to handle the enormous amount of trains that were expected to arrive & depart every day. For a train to be able to reach the proper track when arriving or departing, a bewildering system of switches was built in order to move trains to the proper track without crashing into each other.

Railroads use a system called Interlocking to control train movements through switches.  Interlocking is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings. The signaling appliances and tracks are sometimes collectively referred to as an interlocking plant. An interlocking is designed so that it is impossible to give clear signals to trains unless the route to be used is proved to be safe.

When South Station was designed, the railroads were fully aware of the amount of traffic they were expecting to handle once the station was put in full operation. In the first year of operation, the station handled 737 trains daily.  By 1913 the station handled 38 million passengers annually which was 16 million more that Grand Central Station in New York. In addition to scheduled trains, deadhead movements, car cleaning, etc. this involved about 2,500 movements through the terminal's interlocking plant daily in order to service this many passengers & trains.

Track under control of South Station Terminal Interlocking Plant 1899

To solve the problem of moving upwards of  90 trains per hour, the South Station Terminal needed a large tower to be able handle the enormous traffic load. When the Terminal opened in 1899, there were actually 3 towers that handled all the traffic - Tower 1 (shown here) which controlled the main trackage, and tower 2 which handled the suburban lower loop trackage & interlocking. (Tower 2 was never put into full service as it only handled the underground loop -which was only used only once officially.) Tower 3 was located on the curve just past the Fort Point Channel Bridges. This Tower handled switches at the yard limit for both the NYC and NH approaches.


At the time of the station's construction, the primary method of controlling the movement of the switches was through the use of mechanical levers. This involved a person, located in the tower, to physically pull a large lever mounted to the floor. The lever was attached to system of mechanical linkages to a pipe that ran from the tower to the switch that needed to be thrown. It was all very complex  to operate & maintain since all the mechanical linkages tended to jam or would freeze-up during cold weather.  It also required a large crew of very strong men to be able to push & pull the levers day-after-day.

Mechanical Levers for throwing switches

If a Mechanical  Interlocking plant were to be installed at South Station, it would require a tower 160ft long with 360 levers & 45 feet of space on each side of the tower to accommodate the load out piping that ran from the tower to each switch - all 130 of them. Space being a premium where the station was being built, another solution needed to be found.

After much consideration, the engineers selected the Westinghouse electro-pneumatic interlocking system that was recently invented.  It was a very logical choice as it required 1/3rd the amount of levers, fewer men to maintain & operate, and most importantly, a smaller tower which could be located in the middle of the station trackage for the best view of the switches & signals.

The system to be used at South Station was manufactured by Union Switch & Signal of Swissville PA. while all switches & frogs were manufactured by Ramapo Iron works. The system was installed under the supervision of George B. Francis South Station's Resident Engineer for the project (information on Design & Construction of South Station written by Mr. Francis himself can be found here: Transactions of the American Society of Civil Engineers Volume XLIII )

The entire system was not operational when the station opened in December 1898 so a temporary shack was built until Tower 1 was completed. On May 7, 1899 Tower 1 & its Model 14 Electro-Pneumatic machine became fully operational.

Tower 1

Tower 1 is a 3-story brick structure with a Slate roof and sits in the middle of the track complex. On the first floor of the structure are switch relay cases. The second floor contains the Tower's generating system that converts AC power to DC for use by the machine. The third floor is encircled by windows allowaing a clear view of all track approaches. The Switch machine itself has 143 levers - 130 operational & 13 spares. These in-turn operated 91 High Home Signals, 36 Cautionary Signals, 21 Dwarf Signals, 31 Double Slip Switches, 31 Movable frogs, & 40 Single turnouts. All together this means the switch machine can handle 148 Signals & the equivalent of 233 switches. The levers that control Switches are painted blue, the signal levers are painted red, and the spare levers are painted white.

Interlocking levers & locking bed

Above the machine is a model board operated by minuture mechanical linkages which are mounted on the rear of the board & driven from connections to the switch levers. There are miniature working Semaphores at the top of the model board. A leverman could move a lever, see the actual Semaphore in the Yard change position, and then see the arm of the model Semaphore move to reflect the new position. At the North end (Head end) of the Tower are other indicators which show signal positions.

Tower 2 was built to control switches & signals on the Suburban loop track. This tower (a small 1-story structure located at the tunnel opening to the underground loop) contained a switch machine with a 11-lever Electo-Pneumatic machine operating 8 dwarf Signals, 4 double-slip switches,  4 pairs of movable frogs, and 28 single switches. 

Tower 3 was located at the far end of the yard just beyond the Fort Point Channel bridges. This Tower also had 11 levers that controlled the approaches to the Loop Track as well as the main line approach tracks to South Station for the New Haven & New York Central Railroads.

Semaphores mounted on Signal Bridge

To provide information to the locomotive engineers, the yard used 9 signal bridges to hold the various Semaphores which in-turn displayed if the switches were properly aligned by the Tower.  The Semaphore blades & lights adopted were in accordance with the system used by the New Haven Railroad. The New Haven having recently adopted a standardized system of colors used by the Signaling system: Red for Stop, Yellow for Caution, and Green for Proceed. (replacing white for proceed). This color code was adopted for use in the station's signals. Air cylinders were usd to move the signal arms  & switches with Magnetic valves controlled by wires which extended to contacts of the interlocking machine. Two Ingersoll-Sargent air compressors in the power plant supplied the compressed  air for the operation. One compressor always being held in-reserve as a relay to the other. The air mains were duplicated so that failure in one line with not prevent immediate operation of the switches and signals through the other line.

In the beginning of operations, oil lamps  were used for the signal lights at the station with the exception of one signal bridge, where electric lights were tried on an experimental basis. Why experimental you ask ? because railroads were very conservative operations and something like electric lighting was still young in the minds of many in the railroading business. The "experiment" was likely as pretty good experiment in that by 1904, 182 electric signal lamps were in-use at the terminal.

Model Board with position Indicators

Rail circuits on the station tracks controlled the cautionary signals governing the approach of trains to the station and indicators within Tower 1. A set of 28 indicators (one for each station track) were activated by the rail circuits & showed the presence or absence of trains on the station tracks.

As built, the Tower was directed by a Interlocking Supervisor who, in-turn had an operating force consisting of: a directing dispatcher and his assistant, a telephone attendant, a telegraph operator, and 3 levermen all working on a 2-day shift. During the nighttime, the operating crew consisted of a dispatcher and 2 levermen. Mind you that on a typical operating day the huge amount of traffic generated approximately 28,450 lever movements per day.

The arrangement of trackage allowed for one side to be used for incoming trains while the other side would handle outgoing trains. The weakest part of entire interlocking was the 4 sets of crossover tracks in the middle that allowed trains to access any station track from any direction. If a locomotive or worse, and entire train derailed in the middle of any of the crossovers, it could put anywhere from 50%-100% of the entire interlocking out of service until the tracks were cleared and declared fit for use.

Semaphore Models above machine

The Interlocking plant saw little change from the time it was built until the 1929-1931 upgrade of the station. After the train shed was removed, the number of active use tracks were reduced from 28 to 17 with the decline of traffic during the great depression. In 1934, the new U.S. Post Office was constructed over tracks 21 - 28 which were being used as storage tracks by this time. Also by 1934, with tracks 18-28 not in active service, the Semaphores were removed as they were no longer needed and the Signal bridges were cut back in order to reflect the cutback in service. Signal Bridges 1 & 3 were removed completely, Signal bridge 2 was reduced in size, & Signal bridge 5 was cut in-half.

After the Boston Terminal Company (The operators of South Station) came out of bankruptcy in 1952 the operating plant consisted of 17 out of the 28 original platform tracks, the Loop track & half of the inside yard tracks either removed or out of service. The biggest blow to come to the terminal was when Commuter service was terminated on the New Haven in July 1959. These trains alone, made-up one-half  of the volume of South Station. At this point, tracks 1-9 were declared out of service due to lack of  trains to fill them.  After 1959, Tower 2 was removed, never actually used in active service. The U.S. Post office removed tracks 21 - 28 in order to expand their operation & facilities. The power plant & gas works were declared obsolete and demolished during this period.

By the 1970s, only tracks 8 - 17 were in-service. In 1974, the Railway Express building was demolished & the express tracks removed. The U.S. Post office built several new buildings which permanently removed tracks 18-21. The New Haven (now Penn Central) removed 2 of the 6 approach tracks as they were no longer in-use.

By 1977, only 57 of the Interlocking machine's original 143 levers were working, controlling 55 signals, 17 single switches, 18 double-slip switches, and 9 movable frogs.  55 of the unused levers were removed from the machine while others were reserved as spares.

In addition to the original machine, a 7-lever Electro-Pneumatic machine built in 1939 was added to the tower in the late 1970s  when Tower S.S. 237 (Tower 3) was demolished and the switches were now remotely controlled from Tower 1. A new model board was installed next to the original one inside the tower to indicate track occupancy. By the end of the 1970s, the Interlocking plant served 144 scheduled trains in & out of South Station. This traffic included 24 amtrak trains & 130 Commuter trains.

When South Station was completely rebuilt starting in 1984, Tower 1 was finally demolished as the station, platforms, and trackage were completely rebuilt by the MBTA. Today, there are 13 platform tracks currently in operation with the interlocking controlled remotely from inside South Station in the CETC (Centralized Electric & Traffic Control) Center.

Images of Tower 1 from the late 1970s outside & inside.

Interlocking Machine looking North

Interlocking Machine looking South

Indicators @ North end of Tower

Relay Cabinet on 1st floor

ALTERNATING CURRENT-DIRECT CURRENT' 
MOTOR GENERATOR SET AND POWER SUPPLY 
CONTROLS, SECOND FLOOR

Signal bridges on approach

First Piece of HO Scale Hardware has arrived.

The first piece of hardware for the South Station project has arrived. What is it you ask ?

It is this:

 

#8 Fast Tracks Turnout Jig

The South Station Yard Tracks are very complex. You have 10 approach tracks that need to be able to get to 28 station platforms. In order to do this, you need an incredible amount of switches, crossovers, etc. to get train A to platform B. For South Station,  there are 5 14 degree crossovers, 34 #8 Double-Slip switches, 22 #8 Turnouts, and numerous Turnout Switches that will need be custom-made in order to fit in the yard. See for yourself in this image:

Complex dontcha think ?

I could have gone with commercially-made switches (shinohara, etc) which would have made building this project incredibly expensive. Think of it, If I purchased 34 #8 Double-slip switches from Walthers @ $85.00 per switch, that would cost me $2890.00 just for the slip switches! We won't even get into the costs of the other switches; I did a back-of-the-envelope calculation one night and the amount was staggering. Mind you, this cost is for switches alone. (Need we add-in other stuff like tortoise switch machines, DCC controls , etc. ? )

So, in my usual wreckless manner of thinking, I decided that in order to keep costs down, I would use the Fast Tracks Switch jigs.  I would buy the jigs and build them myself. Simple Right ?

Well, sort of.

John, Have I ever build a hand-laid switch before ? Well, not really. I have hand-spiked track before which was not too difficult to do once you got the hang of it. How hard could it be to advance to making hand-laid switches ?

You can stop laughing now.

If there is one thing I am pretty good at is learning something completely new. Even though my real job is computer network engineering, I managed to teach myself how to design structures, ships, etc using 3D CAD software just because I found it interesting. I have learned if something really interests me, I tend to pick it up pretty quick.

The folks at Fast Tracks took most of the hard work out of making hand-laid switches but creating jigs that you lay the rail and ties into. Then you solder the parts toegther to complete the switch. The end result is a nice-looking piece of track that you built at a very low cost. So, instead of paying $85.00 for the Double-slip switch, The cost is reduced down to about $15.00 plus your sweat equity. The incentive of reducing the cost of making all 34 switches from $2890.00 down to $510.00 is a huge incentive for me to learn how to build switches using the Fast Tracks Jigs.

O.K. John, then why did you buy the #8 Turnout before you buy the #8 Double Slip?

Well, building a #8 Turnout is considerably easier than building a #8 Double Slip switch. I need to learn technique on how these things go together and, most importantly, if I have the skill required to build these switches. Might as well start out easy, gain experience, then tackle the more difficult switches. By the time I build the stock switches, turnouts,etc, I should have enough experince in making hand-laid turnouts to be able to build a genuine custom-made switch.

Well soon find out.

South Station Mechanical Facilities

When the South Station Terminal was designed, consideration was given to having the entire facility, including station, midway, & facilities would be a self-contained Terminal. This means that the terminal could operate without depending on the City of Boston for power, Ice, & Gas for lighting.

The buildings & passenger cars required heat during the winter months. Ice would be required for cars equipped with Ice Air-Conditioning, Power for Electric Light, and finally the Passenger Cars required Pinch Gas for providing Lighting as most cars in 1898 still used gaslights for interior lighting.

The South Station Terminal Company would have to build these structures on-site & close to the  trainshed & station they serviced.  These buildings were constructed at the far end of the trainshed along the edge of track 28.  A switchyard & coal tipple were built in order to bring coal in for the boilers.  Tracks were added inside the Boiler plant to remove the fly ash. The Gas works were build at the far-end of the plant to create & store Pinch Gas. At the opposite end of the building, nearest to the trainshed, the Ice Plant was built to provide Ice for the Station & Passenger Cars that used Ice Air-Conditioning. The Generators for Electrical services were located in the Boiler Plant. Service Tunnels were constructed underneath the station to move Ice for the cars and run the piping & electrical services. 

Mechanical Facilities for South Station Terminal

One of the main uses of the Boiler Plant besides providing steam heat, was to generate electrical power for the entire Terminal Facility. The plant needed to provide power for Lighting, the massive exhaust fans for the underground loops, and most importantly,  power for the the massive compressors that provided air to operate all 137 of the electro-pneumatic switches in the terminal zone. The power room also needed to provide power to the sump pumps for all of the underground portions of the Terminal. Since the terminal was built on a  tidal flat, water was a problem for all the underground facilities in the terminal. Large pumps were constructed throughout the terminal to keep everything dry.

For a detailed description of all these facilities, The American Society of Mechanical Engineers published a journal on the facilities. The South Station mechanical facilities are extensively covered in Volume XXI of the Transactions of the American Society of Mechanical Engineers.  Starting on page 451, the Journal provides an extensive coverage of these buildings. A copy of this Journal can be found here:  Volume XXI of the Transactions of the American Society of Mechanical Engineers.

South Station Post-New Haven

The gullible John Sheridan has carelessly given me the keys to the castle here at The South Station Project. For my first blog post, I'd thought I'd dredge the internet for some South Station photos, showing some of the changes over the years. For this post, all images are from the NERAIL Photo Archive, in chronological order.

South Station was slowly nibbled away after the station was sold to the Boston Redevelopment Authority in 1965. In fact, it was due to be razed entirely before the preservationist movement saved the day and the station. Instead, it was transferred to the MBTA in August, 1979. South Station was the subject of a massive reconstruction project in the mid-1980's where they rationalized the track plan for modern trains and fixed up the rest of the headhouse. They actually built a new Atlantic Ave. wing to take place of the old one that was knocked down, even going so far as to re-open the granite quarries from the original contstruction so as to match it perfectly.

South Station, September 1973 photo by Bruce S. Nelson
http://photos.nerail.org/showpic/?2010020115354617317.jpg

As we can see above, the USPS brick building is in place, eating up almost half the yard tracks. Also, the Atlantic Ave. wing of the station (on the left) has been cut back already. The high track weeds are a common Penn Central affliction.

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South Station, May 1977 photo by Robert B. Clere
http://photos.nerail.org/showpic/?2004012017544232578.jpg

From Summer St. across Dewey Square, one can see how much of the headhouse is missing. Behind the headhouse on the left is the Stone & Webster building looming over the area. This glass & steel building supplanted around half of the headhouse's square footage. On the right behind the tree, one can see white "columns" of the original USPS South Postal Annex, which was built over the high-numbered tracks.

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South Station, 1980 photo by Bill McCaffrey
http://photos.nerail.org/showpic/?2005010621564528355.jpg

One can see just how big the Stone & Webster building is on the right, and the new Boston Federal building (the washboard) is in the background. Pretty amazing how much the city skyline changed from the above 1973 picture.

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South Station, 1985 photo by Peter Kingman
http://photos.nerail.org/showpic/?200703301550262293.jpg

A rare shot of the 1984-1988 reconstruction project. This is the underground commuter station that was never used. The roof monitors are for the Midway, and one can see the old butterfly shed supports at the roof edge. The entire area above the underground tunnel was covered with a corrigated metal deck, some of which is visible here as a pattern on the beam between the levels.

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South Station, 1986 photo by Peter B. Kingman
http://photos.nerail.org/showpic/?200204030252347921.jpg

More during the reconstruction project, showing that the lower numbered tracks are out of service and the butterfly sheds & Midway are gone. All the windows are boarded up, and from personal memory, the inside wasn't much better. A fire at the Club Car bar didn't help, either. I just remember as a kid lots of pigeons, plywood, and grime.

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South Station, 1988 photo by Peter B. Kingman
http://photos.nerail.org/showpic/?2007032205130927898.jpg

Almost done, with only a small pile of rubble visible on the right. The new highlevel platforms are in place, along with the new waiting room taking the place of the old Midway.

Happy Birthday South Station

It was 112 years ago (December 28th 1898) that The South Station Terminal was dedicated.