Awhile back I had a few question concerning the interior of an interlocking tower, which were informativly and courtesly answered. I appreciate that very much. I said before it was my last question, but I was untruthfull, here is another one, but this one concernes the control rods going out to the switches and signals.
Were there two rods going to each switch or just one. Perhaps both answers are correct depending on distance, number of belcranks needed etc. I am installing electric signals so I would assume the signals would be controlled from switches retrofitted in the interlocking plant. As always thank you for your informed answeres. Paul
Dayton and Mad River (model) Railroad
train18393, in the 'Armstrong' towers I worked in, one rod - more like a pipe - went to each switch or signal.
Art
One rod would run from the interlocking frame to the points (with an expansion compensator at the mid-point.) The locking action would all take place within the interlocking frame, inside the tower itself.
Depending on the era and location, the signals could be semaphores operated by cables or by rods, semaphores operated by electric motors or any of the 'light bulb only' types. Frequently, the signals would be upgraded to a later type without modifying the main parts of the interlocking frame or the rodding to the turnout points.
Cable operated lower-quadrant semaphores were in use in Japan as late as the 1960's, and perhaps later.
Chuck
If the switches had been converted to electric motors there would be just one lever to operate the switch points, may only be one lever for an entire crossover. The switch motors have an internal switch point lock mechanism.
For a non electric motor (and non pneumatic) switch the would be two levers, first one would move the switch points and the second one locked them in place. When these two levers were operated you could then operate the third lever to get the signal to operate thru the interlocking.
After the last bell crank which got the switch rod mechanical energy perpendicular to the switch points there was a piece of vertical bar stock which connected the bell crank to the points in which there was two horizontal slots. If everything was properly adjusted the horizontal bar stock at the end of the lock rod would pass thru slot in the vertical bar stock to the switch point and thus "Lock" it in place. The system was designed so the lock bar could only move to or away from the switch bar slots and not sideways. The tolerance between the lock bar and the switch bar slots had to be no greater than 1/8" IIRC.
The signal maintainer showed and explained all this to me when I was breaking in at Thornton Jct, IL. The C&EI had five turnouts in the interlocking that all worked in this manor.
RR Boomer,
Thank you and everybody else for the response. This model tower controlls both mechanical and electrically controlled switches (on my HO train layout.) I have a double crossover with a crossing in the middle and that has electric switch machines with the other nearbuy switches still mechanically operated. Yes I know the prototype didn't use double crossovers often, but it looks great and saves space.
So my follow up question is: would all four sets of points be operated from one lever, and both diverging routes be thrown at the same time? If I am reading into your answer correctly this was sometimes done, depending on the situation. Also if I am interpreting your reply there would be two pipes for each switch on the mechanically operated ones. One for the points and one for the lock. That would explain the pictures of interlocking plants where there appears to be two pipes going to each switch!
I do plan on modeling the disconnected piping still laying around, with the control pipes disconnected as if it was recently upgraded to the electric operation for some reason. I remember tripping over such an installation when I was much younger in the 50s. I also seem to remember that some of the towers had their control pipes in a wooden box that was in the ground and running for some distance to the switches. My experience is in Toledo Ohio, on the east side on the NYC right by Toledo Union Station.
Thanks Again
Paul
Dayton and Mad River(model) RR
There was a crossover at one armstrong plant that I couldn't (at first) move to the Reverse position. What's worse, I could not secure it in the Normal position afterwards. This was during a pre-visit before manning the tower; the towerman at work for that shift, a rather large man, put it back to Normal, but used more force than I could deliver.
Both switches of the crossover were thrown by a single lever. Note that this doesn't necessarily mean a single rod to both switches as one could be to the left of the tower and the other to the right. But if they were on the same side of the tower, a single rod led to the first switch. Rodding was kept to a minimum as extra rodding meant extra maintenance.
One night the dispatcher wanted to route a train on the 'wrong track' and have me cross it back to the correct one. When I told him that I could not throw the crossover, he changed his strategy, and the signal maintainer had the crossover working nicely the next day.
Tain 18393:
As you can see between Art and my experiences a manual crossover could go with either one or two levers. Crossovers that have had electric switch motors installed on both ends could have either one or two levers. I don't think it would be accurate to have two xovers controlled by one lever, but there was probably a prototype somewhere for it.
I never worked at a tower that had both ends of a manual xover controlled by one lever, but it would seem there still would have to be some kind of an arrangement to lock the point(s) in place with a second lever.
Thanks for the insight from people who really know these facilities. Between your information and a good article in Model Railroader several months ago I should be able to accurately model this tower that will be front and center on my model railroad. Usually I don't need such accurate information for detail, bit if I am going to have such a visible model I would like it to look as if it would really work. Thanks again for the information that only somebody familiar with towers could be.
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