Odds and ends
Trunk offer (TKO)
This circuit never had a proper name so for want of calling it something it was known as a TKO selector.
One day while standing watching the trains the phone rang on platform 2 at Ropley, the only member of staff, who happened to be on platform 1 went off to answer it, needless to say before he reached the phone the caller cleared down.
The TKO selector worked in the following manner, to answer a ringing phone one could use another phone dial 6 followed by the number of the ringing phone and answer the call remotely. Safeguards were built in to prevent someone accessing an established call.
Based on a Information Services final selector used for 80XX calls (TIM etc) in a main exchange.
Installed in all four exchanges it can be seen in the picture below on the top shelf at Alresford -shelf position 10
Recorded information services
Sometimes a message needed to be given a large number of people, instead of circulating pieces of paper a number was introduced at Alresford - 2211. This was connected to relay sets which gave access to a recorded message. The message could be easily changed.
The sets are shown above located in a relay set shelf in positions 1 and 2.
Info circuit
Another circuit with no name, most calls were answered by the Information Office on a KLU, if they wanted to transfer the call to another KLU they used the internal system to advise a call was for transfer. Each time this meant dialling a 4 digit number.
A circuit was devised connected to a spare Info Office KLU key, operating the key connected to a relay set which seized a free final selector, dial tone was returned and only the last 2 digits needed to be dialled cutting down on time and wear on the equipment.
Call transfer
Incoming exchange lines were connected to PABX4 exchange line relay sets, calls could be transferred to extensions via an enquiry circuit and dedicated final selectors, seen above - the smaller selectors on the top shelf.
It was also possible to transfer a call to Ropley.
The introduction of the KLUs removed the main need for these circuits except for non KLU connected extensions, this was only fully solved with the introduction of the Panasonic and later switches.
Code phones
There were a number of wooden box phones used to give direct signal box to box service, these didn't work and the telecom department was asked to sort matters out.
On the understanding the old system wouldn't be used each signal box had a small relay set using Post Office 3000 type relays, these relays formed a transmission bridge, controlled calling and sounding a call buzzer.
There were a number of MF signalling Viscount telephones in store, being unsuitable for use on a Strowger system. The key pads were removed, this was the early days of MF phones and was done purely to make sure no one took the phone. These phones were used as the direct box to box phone, the entire system was built and installed in little over a week.
Later several of the old wooden phones had the circuit boards of a Viscount phone installed with varying degrees of success, shown below is the one in Ropley signal box.
During 2008 these phones were fitted with the circuit board from 700 series phones, this is now standard for all "heritage" phones on the railway.
This is the latest variant using the components from a late model 700 type phone. It is a simpler design and makes any maintenance easier.
Clocks
A mechanical master clock was installed at Alresford and eventually fed clock pulses up the line to Alton, it was later replaced with an Electronic Pulse Generator 2A.
One major problem was the cable pairs feeding the 30 second clock pulses to the other stations; this was the time when there was major rodent damage to the cables. Steps attempted to over come the problems were a local EPG being installed at each station, this would run the local clocks if the incoming clock pulse was missing or there was a permanent pulse. Eventually the clocks were removed at all stations except Alresford, nobody complained so there are no plans to restore them.
Power units
With the introduction of digital units in small country exchanges we obtained a number of surplus Power Plant 2040s, these have two 28 amp switched mode rectifiers, only one being in service and two 50 volt batteries,
Each exchange has one of these units, they also run the Norstar switches via a mains inverter. There is also a 50 volt feed to the signal boxes for miscellaneous telephone items located there.
Carrier Some 24 channel Plessey carrier equipment was donated to the railway, the transmission quality of the original cables was poor and it was hoped this would improve matters.
Four racks were obtained and 3 were installed, Alresford, Medstead and Alton, there being no space at Ropley for a rack.
It took some time arranging collection and by the time the equipment was obtained the cables were in terminal decline, although 2 racks were connected and some tests were undertaken between Medstead and Alton the carrier equipment was never used in service.
New cable with a larger sized conductor improved the transmission quality of the analogue circuits, later digital trunks removed the need for the carrier equipment and it was scrapped.
Other carrier equipment obtained prior to the 24 channel system was ex BR valve type and some 4 channel transistor equipment. Neither was ever used.
Two 62 type carrier racks
1 plus 4 carrier shelves
CFDE
Call failure detection equipment - this was salvaged from a public exchange and adapted to work on the railway Strowger system.
The first was fitted at Alresford, when a call was originated the CFDE would connect to the first selector and monitor the digits dialled, within a set time a tone would be expected, if no tone was detected after this period a failure meter would step and the number dialled printed out.
Meters recorded the number of calls to each exchange and the number of successful calls that were answered, it was found a lot of calls were abandoned before dialling was completed. In the picture at the top of the page this equipment comprised of relay sets in positions 5 to 9 of the relay set shelf. A second unit was later fitted at Alton.
Meters from the Alresford unit, found in March 2009 during a stores tidy up.
CressNet
This is the name given to the system linking computers at the various stations.
Inter-station links use 256K digital circuits, although somewhat slow by todays standards they are adequate for the task they perform.
It allows access to the internet and the call loggers at each site, it is planned to connect the alarm system via CressNet.
Each site has a rack for comms equipment located in the exchange room.
Typical comms rack used by CressNet - VDU displaying call logger output
Old comms rack at Medstead
Mobile exchanges
The railway has 2 Strowger caravans, 5 MXE vans containing TXE2 equipment and one used for telegraph equipment on site, all came equipped but are now used for storage.
Happy memories of maintaining a 2000 line MXE unit in Winchester in the late 1970s early 1980s, lots of call outs due to faulty reed relay inserts.
TXE2 van seen at Yateley exchange prior to transport to the railway
Telegraph van at Alresford, it is still on its wheels.
When this van arrived BT got into a bit of a panic as there was something inside which shouldn't have been sent, once retrieved the keys were handed over, the official story was someone had left their tools inside! Whatever its intended use it was apparent it had never been used for such, there was a un-jumpered MDF, the blocks had never been soldered, un-equipped 62 type racks and a Teleprinter 15, with a note stating due to security perforator tapes should be destroyed.
MNDX 105 at Ropley November 2008
Butts Junction treadle
A requirement in the early days of operations was an indication at Medstead signal box when the evening dining train left Alton station. It seems sometimes the train left with no one telling the signalman at Medstead whose first indication of the train’s arrival would be when it arrived at the down home signal.
A simple solution was developed which in different guises still works to this day.
At Butts Junction was a trackside treadle which operated a relay in the Alton telephone exchange which in turn sounded a buzzer in the station office.
An additional set of relay contacts activated an auto dialler relay set, shown below; this dialled a number connected to a relay set at Medstead signal box via the internal telephone system. This relay set would answer the call, sound a buzzer and send a signal back to Alton to release the call. The signalman could either cancel the buzzer or it would auto cancel after a delay.
It was not possible to have a direct circuit between the two stations due to a shortage of cable pairs.
The first attempt was a proper auto dialler which proved unreliable, this was replaced by a DIY set comprising of an electronic sender previously used in STD equipment, a type 4 uni-selector and a number of 3000 type relays completed the relay set.
Over 3000 calls a year were connected by this circuit, I was impressed with this figure only to be told in its previous life the sender would handle that number in a few days.
The circuit was provided on the understanding it was an indication only and not to be relied on, if the telephone circuits were busy between the 2 exchanges on other calls and the relay set activated the call would result in no connection.
Meters connected to the circuit indicated 95% of calls would be connected successfully.
With the introduction of the Norstar switches the Hotline facility was used, the old relay set has been retained for possible future use in the demonstration exchange.
When the new Alton signalling system is in service it is expected this service will be withdrawn.
Taken out of service 5th March 2010 with introduction of Alton colour light signalling.
Shown below is the first attempt - it proved unreliable and was replaced by the version above
Teleprinters
Someone thought it would be a good idea to have a teleprinter at each station, this being before the FAX machine became common.
Some teleprinter 15s were obtained, however they did not have dialling facilities so some means were needed to switch the associated circuits. The printer circuits all terminated at Ropley and to send a message the originator would dial 49XY from a phone, 49 routed to the connecting circuit, X would indicate to the equipment the originating printer and Y the terminating one, the 2 printer circuits were then connected. The caller would hear tones via the phone, one being an indication if the distant printer was switched off.
Replacing the handset would terminate the call.
Despite initial enthusiasm the system rapidly fell into decline and the service withdrawn, recently the connecting circuit was found in a loft, pictured below, minus some bits.
Odds and ends 2
Odds and ends 3
Odds and ends 4
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