Building the railway communication exhibition – part 3

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Completing the works on the main switchboard in the end of May 2016, left us with a room free to set up the main Siemens exchange assembly. As the room’s floor was a subject to dragging a heavy construction of the switchboard and carrier telephony racks, we saved the laying of the new linoleum surface to this moment. After cleaning and levelling of the floor, a new linoleum was laid and glued.

Room was now ready to accept the new exhibit, so we started the painstaking disassembly of the exchange in its temporary location. We needed to start with recovering the original, cast-iron bases and vertical beams.

Designed in the end of 1920’s Siemens exchanges were much heavier but simpler in assembling than the standard acquired by Polish Post in 1931 (based on English Autelco system). The English solution requires moving around with whole racks, which are simultaneously a part of exchange framework. Siemens & Halske took different approach by splitting the construction from functional elements. A basic framework is a frame from angle iron (40×60 mm) of standard length of 3, 4 or 5 metres. Each frame can be filled with racks, each with its individual chassis. Frames are joined together with c-beams (also 40×60 mm). The modularity limits the weight of single parts in cost of the additional parts required to build the framework. Just compare – a single module (depending on the possibility to detach the cables) in Siemens system weights 40 to 150 kg, whereas the Strowger system (in our case the FT-200 exchange) may reach the weight between 190 and 390 kg.

There was a little snag in disassembling the old exhibition – the structural elements had to be recovered first, without compromising the rigidity of the framework. A wooden replacements were used to keep the construction temporarily stable. It was a delicate work – one had to keep in mind to not damage the valuable exhibit, but simultaneously to keep everything from falling apart and injuring the disassembling team. The recovery of the required parts was accompanied by careful removal of existing cable structure.

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