The Demise of The BBMS

London Underground’s Network Operations Centre (NOC) moved from 55 Broadway to a new location near Southwark on 27/28 April 2013, ending over 50 years of the main railway control centre being in the iconic LT/LU headquarters building. Back in May 1962, as part of the de-centralisation of control offices, the then Head Controllers and Information Assistants moved from Leicester Square to 55 Broadway. Many years later, the “Company Plan” of the early-1990s established the “Network Control Centre” with additional responsibilities in its place. In 2005 it was renamed the Network Operations Centre. It is now the London Underground Control Centre (LUCC). One of the functions set up in 1949 was to broadcast (tannoy) messages to certain ticket offices (later extended to some Station Operations Rooms and Line Control Offices). This was called the Breakdown Broadcast Message System (BBMS). With new technology, the old system was shut down for decommission for the move in the early hours of Saturday 13 April 2013 as it was not thought cost-effective to transfer such outdated equipment

I built and installed the BBMS equipment in the NCC to replace that which existed in the old HQ Control Room at 55, Broadway, diverted the hourly clock pulse, sourced from the relay in the 'snake pit' beneath the old Strowger telephone exchange at Leicester square, and also installed the then new BBMS distribution amplifier in the CER built within the old Leicester Square exchange. I spent a great deal of time sorting out the BBMS system improving the audio quality by tracing and rectifying cable faults on all lines.
It is interesting to see the comment about listening to the BBMS, in my experience staff were not that keen to listen to it, I lost count of how many cash bags, sheets of paper etc I found secured over the BBMS loudspeakers in ticket offices and operations rooms when I went to investigate 'no audio' and 'low volume' faults.

BBMS was of course installed in all ticket offices, AFAIR all T/O BBMS loudspeakers were renewed under the UTS refurbishment of ticket offices, I did many of those myself when I was engaged on that project for a while. We also installed them in all station operations rooms, chief booking clerk offices and usually in station supervisor or GSM offices at the larger stations.

For anyone interested in how BBMS worked, it was quite simple really. At the NOC were four desk paging microphones, any one of which could be used to make announcements as the inputs went to a mixer unit and main amplifier within the room. The amplifier also included a chime unit which gave the audio 'gong' time signal when an hourly time pulse was received from the hourly sync relay. The audio was fed to the distribution amplifier at Leicester Square which distributed the audio to separate circuits for each tube line. Along with the audio pair a control pair was routed along each tube line, the control pair operating 'muting' relays to unmute the audio pairs (when there was no signal the audio was effectively short circuited to obviate any line noise from interference and idling line amplifiers) and repeating the control function. There were line amplifiers on each line to boost the audio to the more distant parts of the network. The hourly clock sync pulse operated the muting relays just as the PTT buttons on the desk paging microphones did.

I also designed, built and installed the Traction Earth Detection monitoring equipment and annunciator panel at the NCC but that was made obsolete some 10 years ago as I recall. AFAIK, some of my installations of 30 years ago remain extant and still in use while many of the later ones are long gone!

Moor Park, nice place I used to think when I worked there and nice trackside walking to Croxley or Ricky which I had occasion to do on other projects, longline PA and train radio. Chorleywood was one of my UTS ticket office sites on the Met, Finchley Road was another where I did the comms installations including BBMS. I probably did less BBMS on the Met than other lines, most of my Met work was longline PA, SPTs, station-station direct lines and autos installation/commissioning Baker Street to Amersham, Chesham, Watford and Uxbridge in the late 1980s. In the 2000s it was signal maintenance Finchley Road to Preston Road boundary. Day or night I enjoyed all my time on the Met.

I can imagine that - as deansullivan on the forum says he's not allowed to take his double deckers there as the local residents insist on single decker ones, they didn't want Chiltern's diesels stopping there as they are too loud apparently and I got glared at last time I dared leave the station by someone who probably took exception to my hoody!