Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Interlocking tower interior layout?

6 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    March 2002
  • From: Milwaukee WI (Fox Point)
  • 11,339 posts
Posted by dknelson on Thursday, March 2, 2023 10:24 AM

Some great info and pictures (and modeling) here.  Just a few thoughts about the interlocking tower I visited a few times in my youth.  It was not a crossing, but it was an important junction on the C&NW where the two main lines from Chicago north met at St Francis Wisconsin, and the freight traffic basically went west and the passenger trains and a few freights continued north to the Allis or Marsh yards or the downtown depot (with some local freight switching on that line as well).

In addition to the operator's desk and the interlocking plant (not Armstrong) which faced a panel (which had evidence of many many rearrangements of the track over the decades) with lights (there was also a bell to warn of trains enterring the plant's area) what I remember were the walls.  Hoops for hooping up orders were mounted on the wall, as was an enormous old red megaphone (basically a big cone) which I assume an operator could use to convey verbal messages to a train crewman over the noise of a locomotive or passing train.  There were a number of old train bulletins framed and nailed to the wall and a variety of very old safety posters.  Over the years the operators had also tacked photos they'd taken of passing trains or work crews.  There were also some track tools here and there -- the operator would not use them but they would be handy for quick borrowing by track crews who back in that day used to patrol pretty much all day on their Fairmont "speeder."  Interior lighting was VERY dim.  There was a light at the top of the stairway to the second level.  

The signal bridge with semaphore signals was very nearby the tower, on the line that saw the passenger service.  It was a two track main with current of traffic rules but there were other tracks to allow meets and passes easily.  If the operator needed to hoop up an order he'd do so near the tower's base for the passenger line, but for that important line that went west there was a stand which would hold the train orders on two hoops  one high for the engineer and one low for the conductor in the then-inevitable caboose.  A well trodden path led from the tower to that wooden stand.

Memory is shaky but I think the C&NW had supplied an outhouse nearby for the operator.  I know there was no facility in the tower itself, at least not on the second floor which was the only part I saw.  I never did see what was inside the lower level.

In common with an operator at a depot the desk area had the old fashioned phone with the "scissors" mechanism although there was also a dial phone, a typewriter, railroad radio, a glass top on the desk (with more old train photos beneath the glass), and a place above the desk to put active train orders and bulletins.  A few railroad lanterns (the newer battery powered kind) were hung from nails.  There was a clock and there was a calendar.  

 Everything was old and worn and while not "filthy" everything had a patina of light grime it seemed.  Really the only bright color in the whole place was the light green flimsies hanging from clips above the desk.

Even the operator looked worn and a bit grimy.  He really liked to talk and probably found his job rather boring and lonely particularly once Amtrak took away the passenger trains from the C&NW, and there were no longer operators to chat with in the stations south of St Francis.  I later learned that many railfans used to visit that tower because the operators like to talk to people.  Not so long afterwards the tower was torn down and perhaps all of that old stuff was just so much trash.  


Dave Nelson

  • Member since
    June 2003
  • From: Northeast OH
  • 16,842 posts
Posted by tstage on Wednesday, March 1, 2023 8:02 AM

Wow, Ed!  Even that prototype interlocking tower is in "HO". Wink

And thanks for the detailed pics and video.  That is something that I would love to model on my next layout - within reason.


Time...It marches on...without ever turning around to see if anyone is even keeping in step.

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 15,627 posts
Posted by gmpullman on Tuesday, February 28, 2023 3:14 PM

I enjoy modeling towers of all kinds. There's some distinction regarding interlocking or signal or even crossing tower. I like them all.

In some of my older towers I've installed "armstrong" levers.

 Leverman by Edmund, on Flickr

I believe it is AMB  and GC Laser that makes a laser-cut lever kit. Some railroads had a color code for the levers so I painted some white, blue, red or yellow depending on weather the lever controlled a lock, points signal or was out of service.

In this brick tower I modeled a later electro-pneumatic machine and I used colored fiber optics to represent pilot lights on the board.

 PRR_SG_tower-bay by Edmund, on Flickr

 PRR_SG_tower2 by Edmund, on Flickr

 IMG_5305_fix by Edmund, on Flickr

I have two bi-color LEDs rigged up to the fiber optic and they change as I throw the Tortoise switch machine and you can see the route colors change.

 IMG_5281_fix by Edmund, on Flickr

In my little model RR world there still existed many towers as they were quite common and relatively closely spaced before the advent of "remote" controlled switches and CTC. I've seen instances of areas of busy trackage where a tower was located less than half a mile apart. Even out on the main line towers could be located as close as a few miles. 

With the manual levers there would be considerable rodding and linkage connecting the various levers to the controlled devices.

 Thomas Underwood Coll B&O305 by John W. Barriger III National Railroad Library, on Flickr

 Thomas Underwood Coll B&O228 by John W. Barriger III National Railroad Library, on Flickr

 Thomas Underwood Coll B&O224 by John W. Barriger III National Railroad Library, on Flickr

 031025 fan-hancock_1 by lmyers83, on Flickr

This could be both fun and challenging to model.

Placement: Assuming this would most likely be placed at a crossover track between two tracks, hence the "interlock" term?

The actual "interlock" refers to the system of cams and sliders which prevent certain levers from being manipulated unless a designated sequence of events takes place. This is to insure that a switch can not be thrown in error or after a certain logical route has been setup through "the plant".

 State Line locking room by Jon R. Roma, on Flickr

It can be quite intricate!

This is worth a look:

Good Luck, Ed

  • Member since
    September 2009
  • 80 posts
Posted by Neptune48 on Tuesday, February 28, 2023 12:21 PM

Searching Google for "interlocking tower plans" yielded several drawings, such as this.

Hope it helps.



  • Member since
    September 2003
  • From: Omaha, NE
  • 10,467 posts
Posted by dehusman on Tuesday, February 28, 2023 7:42 AM

Typically the stairways face away from the tracks.

The long axis would be parallel to the tracks.

Along the long axis of the building there would be a cabinet or row of levers to operate the signals, switches and derails in the interlocking.  Above that there would be a model board that displays the layout of the interlocking and what the names/numbers of the components are.  In the other parts there are desks, lockers, stove/heater, water cooler, etc.

On the track side, at ground level there will be an opening as long as the row of levers or control cabinet where all the operating rods come out and go to the various components.

There are three types of interlocking machines, the lever type with a row of vertical levers each about 3-4 feet tall, the pistol grip type, with a cabinet about 3-4 feet tall and about 2 feet wide they a row of handles sticking out of the front (and a glass top) and then a modern electro mechanical with what looks like a CTC panel.

Search for "interlocking tower interior images" and you should hit lots of pictures. 

Dave H. Painted side goes up. My website :

  • Member since
    July 2009
  • From: lavale, md
  • 4,304 posts
Posted by gregc on Tuesday, February 28, 2023 7:34 AM

greg - Philadelphia & Reading / Reading

  • Member since
    January 2014
  • 165 posts
Interlocking tower interior layout?
Posted by ChrisVA on Tuesday, February 28, 2023 7:20 AM


I'm building this interlocking tower kit and had some questions.

Placement: Assuming this would most likely be placed at a crossover track between two tracks, hence the "interlock" term?


I wanted to leave the roof removable and have an interior for the second floor office. I see there are some kits for the interior for a bulding like this. I am guessing it would consist of desks, cabinets, and levers for throwing switches? How would these be placed in the interior?  Assuming the stairways face the track, where would the levers for throwing turnouts go? Towards the window or back? Also assuming the number of levers would equal the number of turnouts this tower is responsible for managing?

Thanks in advance!


Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!