interlocking plant

[train18393]

When a mechanical interlocking lever plant was replaced with an electrical system did they continue to use the original interlocking lever arangement and install the approriate switches in the interlocking mechanisam, or did they replace it entirley with a new model board and all? Could it have been partialy replaced, or did they rebuild the entire tower?

If the old interlocking levers and bars were kept how much of the actuating piping was left in place?

Hopefully some one can help me out here. I have built a Big Four interlocking tower on "stilts" but right now I do not want to go all the way with the piping.

One of the model magazines had an issue that had some detail about interlocking towers, however I have been unable to locate that issue, but I don't think it addressed these questions anyways.

Thanks for any help

Paul

Dayton and Mad River (model) Railroad

[daveklepper]

My experience is that everything was replaced.   NO big mechanical levers left, new conduit for the wiring, not using the pipes and rods of the old installation.   One very good reason is doing anything else would have prolonged the down period when an army of switchtenders was required to move traffic during the changeover.   Instead, everything possible was done to complete the new electric motor and relay and model board installation, with only the mechanical connections to the switch throw rods required for the changeover.   Possibly someone else has a photo of a tower interior with both the full set of levers and the model board with its electric switches and lights both in place.

[BaltACD]

Among the myriad of interlocking's I worked....all forms of conversion were utilized on a case by case basis.....from staying as a totally armstrong, pipeline activated plant; to having the entire interlocking mechanism replaced.  In many cases individual switches and/or signals would be electrified on a plant that then stayed 'armstrong' on other switches and/or signals that were controlled.  In other cases the entire interlocking levers and 'bed' were connected to electric switches/relays to control the plant.  During the period of manned interlocking's, required updates were generally done with prime concern being doing them at a minimum of cost; as even when these changes were being made it was understood that the plants were dinosaurs and would be entirely replaced by CTC in the not too distant, though unknown, future.