Rack at Plessey - selector E2 appears to have a fault 4000 type selectors
Plessey Northampton - removal of exchange
The old exchange went to the Dart Valley Railway along with the B units, if it was ever used again is not known, but I was informed some years ago parts had surfaced on the Welsh Highland Railway at Portmadoc.
The exchange room was a little decrepit so later the equipment was physically moved sideways, the room partitioned and the vacated area renovated, into this area another exchange was installed.
from Turntable October 6th 1984
Two racks from the main Post Office exchange in Winchester, which we had to cut down from 10ft 6 ins, were used to mount selector and relay set shelves from the Plessey exchange.
One rack was used for the line finders and selectors and the other for relay sets.
A ringer rack from the BBC TV Centre with 2 ringers completed the installation.
Again 50 extensions were provided, 4000 type selectors were used initially but were later replaced with 2000 type, a type I was more familiar with.
100 outlet 10 position bank multiples were used, one shelf of 1st selectors, another for second and in-coming selectors and a third for final selectors. Four level 0 and 1 relay sets from UAXs were used as the junction relay sets to Ropley accessing four bothway junctions via junction hunters.
The extensions and junctions were transferred from the old to the new exchange and the old equipment scrapped. A Power Plant 223 with end cell switching was used until replaced by a PP2040.
The Mogul 9th May 1985
A fourth rack, from Itchen Abbas UAX13, was added later for assorted relay sets, a planned 1 plus 4 carrier system and a shelf for a TRT284 call sender.
Later the full width relay set rack was replaced by a narrower one with 5 shelf positions, by that time a lot of the existing relay sets were no longer being used and the extra floor space created was used to instal a 62 type carrier rack, another carrier project that came to nothing.
At this time the Ropley junctions were changed to 2 direct circuits for Ropley traffic and 2 for tandem calls, if both the direct circuits were busy Ropley calls could overflow onto the tandem circuits.
2-10 PBX final selectors were used here and at Ropley.
Selector rack on the right and ringer rack on the left
Two sets of gas combination standby batteries were housed externally in 2 glass fibre cabinets, these had replaced one set of lead acid cells located in the building, later a Power Plant 2040 was installed.
Disposal of the ex BBC ringer rack 2004 Phil Mousley (OIC IT) on the left
Ropley
The UAX12 was replaced by an exchange again built from bits, a PABX3 rack mounting 2 ringers and selector shelves from Ferranti at Bracknell and a Plessey rack used to mount junction relay sets, 50 point linefinders and miscellaneous relay sets.
Ten position bank multiples were used, 4 in total - 1st selectors, incoming selectors, second selectors and final selectors. The exchange was designed from the outset to act as a local exchange plus a tandem switch for the rest of the line although at the time of installation only 2 exchanges were operational. The existing 3XX numbers were prefixed with 4.
With the full opening of the line there were direct circuits to the other 3 stations.
Lack of space in the exchange meant a small power unit had to be used with the standby batteries in external cabinets. Later a PP2040 was fitted.
The old UAX12 went to a Post Office Telephone museum in Brighton, present whereabouts are unknown although someone said it had gone to Amberley, enquiries there have brought no response.
Some years later the third unused Plessey 50 extension line finder shelf went to the Dean Forest Railway and is now in use at Parkend Station .
Shown below - shelf C incoming 1st selectors, shelf D second selectors and shelf E final selectors. Not shown shelf B local 1st selectors and shelf A ringers and associated relay sets
The red labels on the incoming selectors indicated junction guard relay sets were fitted at the far end.
Due to the restricted space it was not possible to take reasonable pictures of the Strowger exchanges at any site.
Box connection that replaced original MDF in the old exchange room, also shown is the EPG2A standby clock and Norstar Startalk unit.
Ropley recovery
The combined efforts of the railway official PW gang, IT department and the Sunday PW gang - telecom department taking the easy option and taking the picture.
Standby 50 volt battery for the Strowger exchange at Ropley
Lead acid cells were changed for 2 sets of gas combination cells, later replaced by a PP2040