Re: Interlocking Towers - why abandoned?

Why is it that years ago the RRs had manned towers at major interlockings. You still see these towers along the NEC and also many freight lines that are still busy today. But, they are all abandoned and borded up. Why do the RRs not use these towers any more and how are the interlockings contolled?

Most Interlockings are controlled via remote TCP/IP Data links. The CTC interlocking controller has a network port, or the older CTC equipment is fitted with an adapter that has a network port. The data from the interlockings is then relayed to the central office computer. Some interlockings even have wireless network connections!

CTC can be controlled from hundreds or thousands of miles away. But not out of the country. At some level a decision was make sure the CTC was controlled.

Amtrak wise is a prime example of this. 21st Street Tower in Chicago controls the CTC in NOUPT New Orleans, part of the Michigan Line, as well as the local interlocking.

More often there is a Large central office. Where you have a number of dispatchers, each controling a segment of trackage often a couple hundred miles long.

I know that on the north end of the nec(SHELL-NHV-BOS) from shell to NHV it is MRCR dispatching. From NHV-BOS it is Amtrak dispatching in boston (right?). Who handles the dispatching from SHELL-south (I know that Amtrak owns the tracks). Also does anyone know who handles the dispatching in/out of penn?

carajul wrote: Why do the RRs not use these towers any more and how are the interlockings contolled?

Best answer to that one, Mr. Carajul, is that as late as 1955, the railroad industry had One MILLION employees. When i "hired on" after college graduation during 1970, the head count was down to about 750,000. Today, it is about 190,000.

Nuff said?

To be even more succinct: MONEY MONEY MONEY.

Everybody gripes about the towers being closed, but the rails are in the best health they've been in since 1910... You can choose what you want, manned towers and a CRI&P-style balance sheet, or CTC and a BNSF-style balance sheet. The only argument to be made is that the people did a better job of moving trains through the interlockers, which I do understand and have witnessed firsthand, but the only place towers are going to be re-staffed is at museums.

Another way to look at it is to use technology whenever it can be beneficial. Long ago staffed towers were needed because there wasn't any viable alternative. However, advances in technology have opened up other options. In very rudimentary form, think of the advantages of EZ Pass versus paying a cash toll.

Ah, towers! When I was a student in Chicago in the early 1970s, I befriended an ICRR towerman (Kensington day operator), and he and I visited essentially all the remaining towers in the Chicago region over the next several years. I wish I had taken more pictures! Even then, it was apparent that these towers were anachronisms, but some had stood for more than a century, so who could have predicted they would be abandoned so quickly?

Towers came about because of the need to control complex railroad junctions and crossings. Originally this was done with "switchtenders", people on the ground who hand-threw switches and signaled trains (with lanterns or flags) to proceed on the lined routes. As trains got faster and traffic volume increased, a way was needed to line routes and signal trains more quickly. The result was manual or "armstrong" interlockings, controlled by cranks and rods, allowing an operator to manipulate switches and signals from a central location (inside a station, in a one-story cabin, or -- more commonly -- on the second story of a "tower"). The first floor of the tower held an "interlocking" bed, a metal frame that physically prevented the tower operator upstairs from lining up conflicting routes.

For obvious reasons, these towers had to be close to the locations they controlled, since the instructions were transmitted by rods and cranks. The largest "armstrong" tower I ever saw was State Line Tower in Hammond, IN, which controlled Erie, Monon, South Shore, and Nickel Plate routes and had a couple of hundred man-sized levers.

Electric interlockings could do the same job as manual ones, and do it more efficiently, and they quickly became the railroads' choice in the early years of the 20th Century. They came in two basic flavors: "straight electric", in which switches and signals were controlled by electric motors, which in turn were controlled from a collection of levers and relays in the tower; and "pneumatic" interlockings, which were electric but which used compressed air to throw switches (and to operate signals, when semaphores were still in use). The PRR was very fond of pneumatic interlockings.

But once electricity was used, it was no longer necessary for the operator to be adjacent to the devices he was controlling. You could put him anywhere. In 1927, the Toledo and Ohio Central Railroad converted three towers at Leipsic Junction to remote operation, called "Centralized Traffic Control". When each tower had a separate operator, trains could get "gridlocked" (the towers controlled three junctions at the vertices of a triangle, less than a mile apart). With one operator in charge, the conflicts wouldn't occur. This was the first installation of CTC in the country, and all it did was replace the large interlocking machines with a miniature "model board". All the existing relay logic remained in the field. it was just controlled from a central location.

We haven't really progressed much farther in the subsequent 80 years. The fancy dispatch centers and "TCP/IP" code lines (or radio) are controlling the same old electromechanical relays and circuits the towers formerly did. Yes, a lot of jobs have been elinminated, but all that relay logic is still in the field, and has to be maintained.

It's time to replace the existing (obsolete) signal system. Much as I miss the towers, I think it's time for railroads to enter the 21st Century.

hi55us wrote:I know that on the north end of the nec(SHELL-NHV-BOS) from shell to NHV it is MRCR dispatching. From NHV-BOS it is Amtrak dispatching in boston (right?).

Yes, NHV-BOS is dispatched from Boston @ South Station

[moved to Operations Forum, since this question is not unique to Amtrak. -omv]

Alcochaser wrote:
Amtrak wise is a prime example of this. 21st Street Tower in Chicago controls the CTC in NOUPT New Orleans, part of the Michigan Line, as well as the local interlocking.

There hasn't been a tower at 21st Street for atleast 3 years. The interlocking is now controlled by Amtrak Lumber Street.

hi55us wrote:I know that on the north end of the nec(SHELL-NHV-BOS) from shell to NHV it is MRCR dispatching. From NHV-BOS it is Amtrak dispatching in boston (right?). Who handles the dispatching from SHELL-south (I know that Amtrak owns the tracks). Also does anyone know who handles the dispatching in/out of penn?

The NYS line ( between Shell and Harold) is controlled by the Amtrak Section A train dispatcher located in the Manhattan CTEC office.

CN_Hogger wrote:

Alcochaser wrote:
Amtrak wise is a prime example of this. 21st Street Tower in Chicago controls the CTC in NOUPT New Orleans, part of the Michigan Line, as well as the local interlocking.

There hasn't been a tower at 21st Street for atleast 3 years. The interlocking is now controlled by Amtrak Lumber Street.

I believe they call Lumber St. CUS south now. At least last time I departed out UP Canal St. The first couple of times after the change I was so used to calling for 21st. or Lumber St. and wasn't getting any answers finally some came over the radio told me call CUS south for departure.

If CTEC signals are controlled via TCP/IP wouldn't that make them vulnerable to hackers? As we all know hackers are a pretty ingenious bunch of people.

NellieBly wrote:We haven't really progressed much farther in the subsequent 80 years. The fancy dispatch centers and "TCP/IP" code lines (or radio) are controlling the same old electromechanical relays and circuits the towers formerly did. Yes, a lot of jobs have been elinminated, but all that relay logic is still in the field, and has to be maintained.

It's time to replace the existing (obsolete) signal system. Much as I miss the towers, I think it's time for railroads to enter the 21st Century.

At least in my limited experience the days of the relay are rapidly disappearing. Most of our interlockings and grade crossing systems have gone solid state. In the old days the signalman would say to us track dogs, "That insulated joint is bad. Change the papers." Then, they would fix the real problem. Nowadays, a lot of the time they don't know what the problem is. They just swap cards until the thing works again.

In my non-Signal qualified opinion these solid state systems are not as robust. Every time there is a lightning storm there are problems all over the place.

DAW

The signal system uses dedicated phone lines or fiber optic cables to get signal from Dispatcher to CP point.
The signal is not TCP/ip but old fasion pulse code.