Interlocking Towers

[tomikawaTT]

First, let's go back some decades before the transition era, to a time when an interlocking tower contained an interlocking machine - a massive metal conglomeration of levers and rods, with huge handles moved by brute force to change the position of switch points and signals, some of which could be several hundred yards away.  The machine was so arranged that the operator could NOT clear two trains through the same point at the same time, nor could switch points be moved once the appropriate signals were cleared.

As time went on first signals and then points were powered by electricity (or maybe air, through electrically-controlled valves.)  The massive handles gave way to smaller controls - but the same principles still applied.  The tower gave the operator a good look at what was happening.

Enter track detection circuitry.  Now there was a nice track diagram above the controls, with little lights that moved along to show where rolling stock was located.  Eventually, that made the tower itself unnecessary - the controls and track diagram didn't have to be anywhere near the physical signals and switches they controlled.  They could be in another town, or even another state.

By the transition era, most interlocking plants were electrical, but the towers were (mostly) still there and still staffed.  Not much later they would be boarded up, or razed, with signals and switches controlled by CTC operators.

If there was a yard entered from a main line with significant traffic, there might be an interlocking tower at each end - but each would only control the switches involved in the main line junction and their associated signals.  There might be ONE interlocked switch point set, on the turnout that allowed a departing train on the yard lead to move onto a main track (or vice versa.)  Most of the time those points would be aligned to allow free use of the lead for yard switching.

Chuck (Modeling Central Japan in September, 1964 - with electrical interlocking)

[BRAKIE]

Actually I know of several interlocking towers that did in fact controled the movements of inbound and outbound trains plus the by pass tracks. Of course these was busy terminals that seen 60-70 trains entering or leaving the yards..The PRR also used switch tenders to help line trains into or out of the yard.These switchtenders was uncontrol of High St tower on the west end and the Joyce Ave  tower on the East end.

Know and understand there was several yards in this yard complex that served 4 sub divisions and each yard had a yard office.These offices  was under the control of a GYM..

Also NYC had a interlocking tower thar controled inbound/outbound trains at McKiney Ave yard.

These was not "yard towers"..

 

[cv_acr]

To tie together what Dave H. says above, yards and interlocking towers really have nothing to do with each other conceptually, although if it is a significant mainline and a sizeable yard, there could be an interlocking protecting the junction between the mainline and the yard entrance.

Only the main track and junction switches would be interlocked; all the switches inside the yard would be hand-thrown by the train and switch engine crews. (Except for switches related to the hump, if this is a hump yard, which would be controlled by the hump operator.)

In most small to medium sized yards, the yard office (if it's even a separate building and not just located inside the station) would just be a small one-storey structure and not a "tower". Large control tower type structures for the yard office are typically only found at the largest yards.

[yankee flyer]

Hey 

I got a look at the yard office  in Dupo Illinois And found out they don't use the tower for normal operations. Everything is done on computer screens. They do use the tower for a training room on occasion.
Not a very friendly bunch.    I would have loved to had a tour of the tower.

Have fun.

Lee

[dehusman]

Yards do not have interlocking towers.  Manual interlockings may have interlocking towers.

Some yards may have yard towers.

Yard towers and interlocking towers are two different buildings.  A yard tower is basically a elevated office for the yardmaster.  The interlocking tower contains the interlocking machine that operates the interlocking.  A yard tower may be taller than an interlocking tower, some are 4-5 stores tall and may have multiple offices in them.   An interlocking tower is almost always only two stories, the top story for the controls and the operator and the bottom for the rodding and mechanism.

Yards may or may not have towers.  Depends on how much the railroad wants to spend and how complex the yard is.  The majority of major classification yard may have had one or more yardmaster towers, the majority of industry support or local yards did not have towers.

[Canadian Big Boy]

Did rail yards have interlocking towers at both ends of the yards or at just one end?

Or does it depend on the size and complexity of the yard?

I'm buliding a steam transition era layout.

Thanks

Sheldon