21 members met at 09.30
outside Norwich Thorpe station on a hot sunny day. After a safety briefing from host and guide, Local
Operations Manager Adrian Webb, the small convoy headed off to the nearby Trowse Swing Bridge.
https://goo.gl/6Q5SBf Hidden away, the box is accessed very obscurely through Colman's Factory (NR
do have running powers!) and, after being waved though Security (obviously as keen as mustard!), the
box was reached via an internal road which does not appear on any maps. There was some discussion
on the day about this access road and if it might have been on the course of a previous internal siding.
On opening in 1987, this was just a Bridge Box controlling the River Yare swing bridge on the Norwich
to London main line. As part of electrification and resignalling, a new single track bridge was
constructed. The previous bridge, the same design as Oulton Broad (visited later), was double track
and remained in use while the new bridge was constructed and tested alongside. It has an unusual
rigid overhead metal AC conductor rail (known as a 'bar conductor'), which we were able to view close
up, instead of overhead wires. The bridge is out of use to tall boats and can only be operated
manually, a rare event. River traffic is advised that it is unable to be opened by two red flags on the
roof of the box (as elsewhere). If a swing bridge is available to 'open' for river traffic, then one red flag
is flown. A double track replacement has been suggested for this single track rail bottleneck which
causes delays. For the options being considered see (BLN 1221.1708).
Around 1988 the Norwich area 'emergency panel' was moved to Trowse Swing Bridge box when
Colchester took over control of the area. This panel was first commissioned on 26 January 1986 (with
the area subsequently extended) in a temporary 'Norwich Box', just south of the station on the Up
side. If Colchester loses control of the Norwich area, the panel can be switched in and operated under
the supervision of a Colchester signaller. It cannot be operated as a 'block post' in its own right as
there is no telephone concentrator (railway jargon for a mini-switchboard). Some of the signallers in
the box use the panel display to help regulate conflicts at Whitlingham Jn, as they can see if any
services are delayed leaving Norwich. The final piece of the jigsaw is the Vaughan Harmon Modular
Control System VDU workstation, commissioned in 2000 to control Whitlingham Jn and the
Sheringham branch. It works track circuit block to fringe with Brundall and Colchester (Norwich Panel).
The signaller sets routes using the entrance/exit principles either by using the tracker ball or the
keyboard. As well as supervising a CCTV crossing at Walpole, the box looks after several other
Automatic Half Barrier and user worked crossings. There is an old style gong on the wall above the
workstation which is the emergency alarm from Colchester. This was tested during our visit with 16
bells – 6 (obstruction danger!). It makes a pleasant change from the screech of the new style alarm
from Brundall Box, also tested during the visit, but there would be no mistaking which alarm is which!
After thanking the duty signaller, the group made for the rather isolated Somerleyton station for
Somerleyton Swing Bridge over the River Waveney. Prior to making our way to the box, via the
authorised walking route, Adrian took a line blockage. This procedure, repeated on returning to the
station, was required as a safety measure due to our group size and because the walking route was on
or near the running line. The box works absolute block to Reedham Swing Bridge and Oulton Broad
North boxes. The 1904 Great Eastern box has a 14 Lever McKenzie & Holland frame and the bridge
control equipment. The provision of outer home signals in both directions means the bridge can be
swung without the need to 'block (the line) back' to either of the adjacent boxes, unlike at Reedham
Swing Bridge. The Down signals (SB7 & SB8) are shown as having detonator placers but these are no
longer used as NR is unable to source detonators! In order to avoid delaying trains, the signaller is
instructed not to swing the bridge for river traffic after accepting a Down train from Reedham.
The most remote location visited, only accessible by walking along the railway or by boat, note there
was a line possession and the bridge is open to river traffic anyway. The single red flag flying indicates
to river traffic that it can be opened if required. A double red flag indicates that a bridge cannot be
opened, for example unstaffed, stuck or broken down.
[© Andrew Gardiner 2015]
As it was the peak summer season river traffic was busy and the bridge was opened and closed several
times during the visit. This allowed members to observe proceedings from the signaller's perspective
on the operating floor and from a place of safety behind the box. The basement locking room (which
also housed the two electric motors for the bridge) was also visited. To swing the bridge one motor
releases the wedges which keep the bridge fixed and at the right level for rail traffic; then it rises about
a foot and is finally swung by a cable pulling it. The process is reversed to close it to river traffic.
Instructions (more complicated than might be imagined) for operation were on the wall of the
[© Andrew Gardiner 2015]
While the signaller usually keeps an eye out for boats, they can make contact by VHF radio. Wooden
advice boards attached to the box have been replaced by a screen-based system controlled from the
box using a laptop. These advise river traffic of when the bridge will open and for how long. In addition
to controlling the bridge, the box releases a ground frame for a trailing crossover just south of the
station. It is electrically released by Lever 5 but is rarely used (mainly during engineering work) and is
expected to be removed with resignalling.
During a line possession, the BLS Orange Army returns after a successful invasion of the
normally tranquil and remote Somerleyton Swing Bridge box; a ¼-mile northwest of Somerleyton
station with no road access. The box and one of its semaphore signals is on the horizon round the
curve in the middle of the picture. The bottom of the Lowestoft (Down) P2 north end ramp is at the
foot of the picture. A relatively unusual feature nowadays is that passengers have to use the Barrow
Crossing shown to reach and exit the Norwich Up direction P1 (left). Despite the station's remoteness
it has a train every two hours to Norwich and Lowestoft although services do not stop on Sundays.
[© Andrew Gardiner 2015]
Next was Lowestoft an 1885 Great Eastern box with a 61 Lever Saxby & Farmer Duplex frame installed
in 1905. It controls the three platform station, (P2-4 as P1 no longer has track) as well as a relatively
extensive, but heavily overgrown, set of sidings and works absolute block to Oulton Broad North.
Routing codes are added to the normal 'Is Line Clear' bell code to let the signaller at Oulton Broad
North know if the train being offered is for Ipswich or Norwich. While traffic is relatively light, this
feature is useful if the schedule is altered.
The box is extremely well kept, with a polite notice on the block shelf asking signallers to always make
use of the lever cloths provided. Other interesting features include the foot press electrical releases for
points and facing point lock levers, locked by track circuits. The signaller has to press them with his
foot when operating these levers. If the respective track circuit is free, then the lever will be released
electrically. While they need to be operated for point lever movements in both directions (i.e. normal
or reverse), they only need to be used for facing point levers when the points are being unlocked (i.e.
it is possible to reverse the lever and lock the points even if the respective track circuit is occupied).
Trains approaching the station are advised of their route by a theatre route indicator on the inner
home signal. This will display '2', '3' or '4' for the platforms or 'S' for the Sidings. While the indicator
itself is operated electrically, the levers are all mechanical. Prior to operating the lever for the signal
itself (lever 57 main arm or 38 calling on arm), the signaller will set the route and then pull the
respective route lever (53, 54, 55 or 56). The route is then proved by a combination of mechanical
interlocking in the box and mechanical detection outside on the ground. Adrian showed the group the
latter feature, which was clearly visible from a place of safety; a sort of Victorian mechanical
computer, with numerous wires and rods but safe, effective and had certainly stood the test of time.
While the distant signal is now fixed at caution (as it is defective), it was previously worked; relatively
unusual for a terminus because buffer stops are considered to be a signal at danger.
Oulton Broad North was then visited. As well as the junction with the East Suffolk line, the box
controls the very busy A146 level crossing. Despite signallers doing their best to minimise delays to
road traffic, this is a hot topic locally and was challenging to members of our group trying to take
external pictures from the other side of the road! This 1908 Great Eastern Box was extended in 1928
when Oulton Broad North Junction Box was abolished. It has a 35 lever McKenzie & Holland frame and
works absolute block to Somerleyton Swing Bridge and Lowestoft. The former Radio Electronic Token
Block (RETB) working has now been replaced by track circuit block on the East Suffolk line where it
continues to work to Saxmundham, aided by a VDU train describer. As there are no slot arrangements
in either direction, it is in theory possible to have a 'Mexican standoff' as there are no controls
preventing both signallers setting a route onto the East Suffolk single line at the same time! While
there is no risk of collision as there are intermediate signals on the single line, the train from Lowestoft
would need to reverse if this issue was ever to arise! The Up line from Lowestoft is fully track circuited
despite being operated as an absolute block section. This feature allows the Oulton Broad North
signaller to send 'train out of section' to Lowestoft even if he has not seen the tail lamp; particularly
useful as East Suffolk trains do not pass the box (it is on the Norwich line west of the actual junction).
The box also controls Victoria Road Level Crossing by CCTV. Lever 20 electrically releases for Oulton
Broad Swing Bridge. Additionally slots are provided on the protecting signals 19 and 21.
After a short walk the group arrived at the penultimate location, Oulton Broad Swing Bridge 'opened'
(!) in 1907. It differs from Somerleyton, and Reedham, in that the bridge control cabin is on the Bridge
itself rather than in a riverbank signal box. This means the signaller actually 'swings' with the bridge
and, in the event of a (rare) failure, would be trapped and need rescuing by boat! It must be quite a
nerve wracking experience the first time the signaller operates it unsupervised. A separate signal box is
provided; a modern temporary cabin replacing the original signal box that was condemned in 2005.
The previous 1907 vintage Oulton Broad Swing Bridge, the upper section was removed in 2005
as it became unsafe;
the 10 lever frame went for preservation at the 7¼" gauge Barton House Railway,
The lower locking room remains but looks very odd with its flat roof.
[© Angus McDougall]
The bottom of the original box is now an equipment room. As it is now in effect the equivalent of a
'gate box' and not a block post, a release has to be provided by Oulton Broad North (rail traffic
permitting) before the bridge can be opened. In addition to this release, the signaller takes back the
slot on the two protecting signals using a small panel in the cabin. This then releases a mechanical
lever on a small ground frame which unlocks the bridge by withdrawing the bolts. It was demonstrated
to the group several times, as a release was taken to protect each group while they visited the bridge
control cabin. One group had the pleasure of being 'locked' in the Bridge Control Cabin to allow a train
to pass. Of note was the two-cylinder Tangye hydraulic pump to release and reposition the wedges
that fix the bridge in position when in its railway operating position, still using water as the medium.
Oulton Broad bridge swings much less frequently than Somerleyton and Reedham; the opening times
are co-ordinated with the Harbour Master (in fact they have to be booked 24 hours in advance).
During the winter the river is only open to traffic for a few hours daily, although the bridge is staffed as
the signaller might need to check the equipment if the train detection fails. Although the East Suffolk
line was mostly singled years ago, double track is retained on the bridge (the Down line disconnected)
to balance the weight. Entering the Bridge Control room is like stepping back in history into a museum
and it is easy to forget that this is an active operational location on a modern railway. This is
emphasised by the original LNER operating instructions on the wall which still apply. These also
confirm this bridge was the same design as the original Trowse bridge. See https://goo.gl/rV24RT
Final port of call (!) for the day, was Saxmundham box which dates from 1881. In 1986 the East Suffolk
line was rationalised and controlled by the RETB system from it. A small individual function switch
panel was also provided to control the Sizewell Branch connections. To increase line capacity, the East
Suffolk line (which came very close to being a Beeching closure) was re-signalled in 2012. A new
passing loop was provided at Beccles, allowing an hourly service which has resulted in 34% passenger
growth on the line in 12 months. The line is now controlled from Saxmundham using a miniature
electronic system, similar in operation to Trowse Swing Bridge. Track circuit block regulations apply
throughout, using axle counters. It fringes with Oulton Broad North and Colchester (Ipswich Panel).
The Sizewell branch is operated under train staff & ticket regulations with a divisible train staff. In
addition to the train staff section, there are two segments of it which can be unscrewed known as 'the
tickets'. If more than one train needs to run on the branch, in the same direction of travel, the first
driver is issued with segment 1 of the staff. He is also shown the main staff (and segment 2) which
proves to him that no train can be proceeding in the opposite direction. Stop boards exist at the end of
the branch and once the (complete) first train has arrived within the protection of the stop board, the
signaller will be advised accordingly. He can then repeat the process using segment 2 for a second
train. The last train to proceed in that direction will take the train staff itself (with or without the other
two segments attached accordingly). Once the whole train staff is at the end of the branch, trains can
then start to return to Saxmundham using the same process. This method of operation is relatively
rare, but not unique, on NR. In addition to operating two barrier crossings from the box, the signaller
supervises 26 user worked crossings and 23 automated crossings on the main line and two user
worked crossings on the Sizewell branch. The automated crossings are a mix of barrier and open
crossings, all locally monitored. The signaller will receive several hundred calls per shift, particularly
during the harvest, and is therefore kept very busy despite the standard train service being hourly in
After a most interesting day with superb weather in a lovely area, the group thanked
Adrian. In appreciation of the facilities kindly provided, £400 was donated by participants to the Isle of
Wight Steam Railway, Adrian's chosen good cause.
For more pictures by Andrew Gardiner see https://goo.gl/e73HZK.