Interlocking Towers

Discussion in 'Model Rail Operations' started by tetters, Mar 20, 2008.

  1. tetters

    tetters Rail Spiking Fool!

    In my quest to model prototype buildings for my fictional railraod, I came across a set of decent blueprints for a "CPR Standard Interlocking Tower". I found the plans on the Canadian Pacific Historical Society website located here.

    CPHA: Canadian Pacific Historical Association Documentation Project

    You must register in order to search and access the on-line library however it is a painless process. Best thing...its free.

    I'm assuming that this little guy is pretty much the equivalent of a yard tower...except it appears to be smaller as the building itself has a scale foot print of only 12 x 12 feet. 30 feet in height, two complete floors with a ground level deck. Looking at my layout and the amount of real estate this guy is not going to take up any room at all.

    The question I have is, would this single tower at one end of the yard be built to handle all of the yard switches or would/could there be two at each ladder? We are talking about 20 t.o.'s in total. Just looking at it, I cannot see how it would be possible, as the personnel manning the tower would not be able to see over all of the freight cars to the far end at either side. Although, come to think of it, I may have a spot for it, where the ladders can be "seen" at both ends and a single tower scenario is possible. Also, it lookes like you want it in a place as well where the people in the tower are close enough to the track side so that they can converse with the engineer while in the cab.

    I plan on hitting the library tonight to get some more material for studying however, I'd like to hear some first hand information from you fine folks here.

    Thanks as always.
  2. Triplex

    Triplex Active Member

    An interlocking tower is not a yard tower. They were located at junctions and the like.
  3. 60103

    60103 Pooh Bah

    An interlocking tower would not be handling the switches in a shunting (freight) yard. They would handle traffic at junctions or the ends of stations.There are 2 at Toronto Union Station; one is under the bridge to Skydome and it handles all the slip switches from the platforms out and probably the junction out by Bathurst St. There's a video on it available.
    Yards tend to have manual switches as there's less traffic and speeds are lower -- no interlocking and signals required.
    I'm not sure how many levers would fit in a given tower; I think 6" spacing seems about right. In mechanical days, there would be a lever for each set of switch points, in some situations a locking lever, and a lever for each head on a signal. In Britain there might be additional levers for detonators that could be placed on the rails beside signals in fog.
    There were distance considerations on placement of towers. Signals could be controlled with wires, but switch points were powered by iron pipes: to change a switch 500' away you had to move that much 1" pipe 4 to 6".
    (subject to amendment by the guys that know Canadian signals practice.)
  4. tetters

    tetters Rail Spiking Fool!


    So perhaps I should save my real estate then for a yard office and other structures, like maintenance sheds and loco maintenance. I've just seen Yard Towers on just about every layout so they seemed like belly buttons...everyone's got one! LOL!!!
  5. doctorwayne

    doctorwayne Active Member

    I think that the reason we see so many on various layouts is because they're so "railroady" looking. I used three of them on my layout, mostly because I already had them, and I liked the way they look.
    The tower at Airline Junction supposedly controlled the three switches that make up the Junction, although I haven't decided whether it was through rods and levers, as David suggests, or via electrically-powered switch motors. Since the connecting railroad's track has been mostly torn out, the area now serves only as a wye for turning locos and the odd car.

    The one at Cayuga Junction will eventually control the switch giving access between the Grand Valley and Erie Northshore track, and may also be equipped with a train order semaphore.

    The Port Maitland tower controls interchange traffic between the Erie Northshore and the TH&B, via telegraph, but controls no switches. The building was dismantled and moved here from a location where it was no longer needed, and now houses the offices of the Yardmaster and Traffic Department, with a crew lunchroom on the ground floor. I may also install a train order semaphore here.

  6. brakie

    brakie Active Member

    Guys,Interlockers could be found near the yard throats and passenger terminal throats.These would control the inbound outbound and run through (bypass) tracks.
  7. railohio

    railohio Active Member

    Yay! I get to argue with Triplex again. Once again, brakie is right. Towers could be located anywhere there was an interlocked junction. This might be at a diamond (though there were diamonds out there with no sort of interlocking mechanism), crossovers, yard, or simple siding. The term interlocking simply means that the track and signals are connected (interlocked) and operate together. Many modelers I have seen misuse towers as scenic elements rather than as they would appear on a prototype.

    Pertaining to the topic at hand, many yards would have interlocking towers at each end to control movements between the yard and the mainline(s). Within the yard, however, switches would be controlled manually or by the yard's control tower. Most main lines have a form of traffic control on them and the interlocking towers are an extension of this. A train can move along the line or on to it from a yard without contacting a tower operator or dispatcher. Within yards, however, trains generally operate on the basis of "yard limit" rules which boils down to the "don't hit anything, dumbass" rule. As such the need to control movements within the yard would be minimal.
  8. b28_82

    b28_82 Member

    My dad still works in an interlocking tower and it is near 3 yards but doesnt control any of the switches in the yards themselves. However you couldn't see any of the yards from that tower because of the proximity. Here's an aerial shot of his tower Dolton (pronounced more like dalton) Live Local Search The UP goes north-south the IHB goes East-West and the CSX goes East and curves to the Northwest. What's crazy is they are all double tracked and as you can see there's multiple interchange so diamonds galore.
  9. tetters

    tetters Rail Spiking Fool!

    Thanks for the all the replies gents. Looks like I can bash one of these guys up after all.
  10. acsoosub

    acsoosub Member

    Big difference between yard towers and interlocking towers.

    Interlocking towers control, well, and interlocking. An interlocking being a section of track with all the switches and signals tied together to a signal control system. In the old days, manual interlockings would have been common. (There'd be big levers in the tower, connecting to a rod system that runs out to each switch and signal. Signals in this case would be old style semaphore blade signals.) Then along came computer controlled interlockings with light signals and powered switches. Nowadays a lot of interlockings are fully automatic, with no tower operator required.

    An interlocking could be protecting a crossing of two railroads, a junction, or something as simple as a crossover.

    A yard tower doesn't control any switches or signals. (Exception, hump control tower) It's the yard office for controlling traffic in the yard. In major yards it's often elevated and built as a tower so that the yardmaster can see the whole yard from the office. In smaller yards it might just be a room in part of the station, or a shack in the yard somewhere.
  11. 60103

    60103 Pooh Bah

    There was another type of tower that you sometimes see. A very small tower, raised on a narrow framework and often sited between tracks. These controlled crossing signals and gates, usually in a city where there were lots of crossings close together. The tower was raised so that the operator could see trains coming and judge when to close the gates -- or open them if the train was stopping or switching.
  12. doctorwayne

    doctorwayne Active Member

    Still need to build the gates: ;):-D

  13. brakie

    brakie Active Member

    Chris,The interlocker that controls the inbound/outbound/by past tracks IS NOT a yard tower.These are fully functional interlocking towers use to control train movements in and out of the yard.These towers could be also found near the throat of major passenger terminals as well..
    There are many examples of such interlocks and many are still in use today.
    A HUMP TOWER only controls the hump bowl switches and retarders and NOT the inbound/outbound/by pass track..The yard is usually control by the yardmaster.His office is found in the YARD OFFICE which is usually found near the flat switching classification tracks.
  14. acsoosub

    acsoosub Member

    Larry, quite true.

    What I meant was, some larger (flat) yards have elevated towers for the yard office where the yard master & car control clerks etc. can see the yard from the office.

    In this case yard tower = yard office

    I wasn't referring to any interlocking towers that might control interlockings leading in to the yard, sorry for any confusion. In that case, they're an interlocking tower just like any other - nothing special there.
  15. brakie

    brakie Active Member

    My bad as well..:oops:

    A example of a elevated yard tower can be found on the NS at Bellevue(Oh).Its called "Ranger" tower.
  16. tetters

    tetters Rail Spiking Fool!

    So let me get this straight.

    An interlocking tower could be located in a place where it would control t.o.'s to access a yard but not actually control the movement of the yard switches themselves.
  17. b28_82

    b28_82 Member

    Basically yes. An interlocking tower is designed to control movement on the mainline. So the only switches it would control at a yard would be the ones allowing the train onto the mainline.
  18. acsoosub

    acsoosub Member

    Kinda. An interlocking tower controls an interlocking, and that interlocking could really be all kinds of things.

    But there's absolutely no reason ever that you would want to interlock or otherwise control switches inside a yard from a central tower. Yard switches are always manual.
    Switch crews, by the very nature of their job are always moving cars from one yard track to another and you want them to be able to throw their own switches. If they need to ask some tower operator to throw a switch for them every time they back up, no work would ever get done.

    Interlockings or any sort of CTC signalling would only be installed on the mains and at the switches that join up with the mains. (Note that small spurs off the mainline to an industry won't be set up as an interlocked junction. Just a locked manual throw switch.)
  19. brakie

    brakie Active Member

    And the inbound tracks as well as the bypass tracks.

    Also please note that these tracks are usually govern by signals as well.
  20. b28_82

    b28_82 Member

    Well yes, I was generalizing it for simplicity. There are always differences when it comes to the area you are at. I consider the bypass tracks the mainline because in certain cases they are labeled as such. M1, M2, 1, 2, 3, 4, 5, and so on.

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