Gopher! OR The Invisible 'Train'

[StevieG]

Arising from parts of a couple of posts in the "Let's go for a spin!" thread in this forum, including a comment about the thing probably not operating track circuits, I was reminded of what was, in the experience of at least some 'modern' (1980s) power signal box staff members, a strange 'train'-running journey of which to be in charge of its signalling.

One night (early hours) in the early-mid '80s, an engineers' On-Track Machine was due to run from somewhere on 'the GE' to Hitchin Down Yard, via Victoria Park, Dalston, Canonbury Tunnel, Finsbury Park, and down the 'GN' main line.
The machine was called a 'Tracgopher', I believe intended to bring some mechanisation to the job of digging small bores or trenches, under-track or trackside ; a type of machine which I have never set eyes upon, but which I understood might be smaller than an average OTM; and I had gained some impression that BR had few of these.
This OTM was to travel under the standard instructions for movement (on lines open for traffic) of On-Track Machines "...not guaranteed to operate track circuits".

[ Sorry, but, to set this up for the uninitiated to hopefully comprehend the tale, I am realising it may take a lengthy preamble; hope it's not too boring.]
The safe signalling of trains under the combination of power signalling and use of the track circuit block system relies on each train protecting its own safety by its position being continuously detected, in most cases by track circuits, and thus, through the signalling interlocking, preventing other trains being signalled into it and accidental operation of points ahead of, and beneath it.

Train detection in the control area of King's Cross power signal box, was at that time effected by track circuiting throughout, and that is probably still the case.

To ensure safe movement of a 'not-guaranteed...' OTM (hereinafter in this story, referred to as "the machine") and other nearby trains, these instructions allowed the machine to be signalled normally, but to compensate for the machine not reliably operating the track circuits, the instructions included three important requirements :
1) The machine stopping at various strategic signals for a member of crew to report/confirm its whereabouts;
2) The signalman, while setting his/her routes of controlled signals for the machine to proceed from each point A as far as the next reporting point, B, had to additionally 'double-lock' all box-operated points in those routes, in the correct positions for the machine's routeing (done electrically from the box, by their individual control switches in addition to their being locked in the normal way by signal routes set through them); and
3) Had to maintain the setting/locking of the signal routes and points until certain that the machine had passed beyond, nor allow any other train to follow the machine without being absolutely sure that the machine was protected by at least one signal maintained at Danger by the signalman.

Typically, 'not guaranteed...' machines, would operate the majority of track circuits, most of the time, occasionally 'disappearing' from the signal box control panel for several seconds, or a couple of minutes, presumably through one or more of some factors such as insufficient weight, precise profile and cleanliness (or otherwise) of railhead and wheel treads, speed, manner of motion (e.g. oscillation or slight rocking).


So, to the 'Tracgopher' story.
The machine was Described [approach-advised by receipt and display of its headcode/reporting/ID number (delete as preferred) ] to us in King's Cross box from Western Junction box (Dalston) which then controlled the Hackney Central-Canonbury Junction area, so the panel 2 signalman set routes, and the signals cleared, for it to proceed along the Down Canonbury and Down Goods lines as far as the DG line in Finsbury Park station, signal K391.
Next thing we knew, perhaps 10 minutes later, was a phone call from K391 to say that the machine had arrived there! It's Description was still in the '1st train approaching' position on the panel, all signals still 'off' behind it, and it hadn't shown up on the panel once!

After putting the signals back to red behind the machine and giving 'Train out of section' to Dalston, the signalman set and locked up the routes for the machine to set off again, along the Down Slow No.2 as far as Hornsey, from where the panels 3, 4 and 5 signalmen continued setting up for it, to cross at Wood Green (now Alexandra Palace) to and along the Down Slow line all the way to north of Hitchin (except, of course, running via the Down Main through the double track-only stretch from Digswell to Woolmer Green), and the machine set off from Finsbury Park.

But we were overlooking something, K453 signal, in this case being used for crossing the machine from the DS2 line to the Down Slow at Wood Green, was always approach-released from red by track circuit occupation (to restrict trains' speeds before traversing the crossover) : - There was soon a telephone call from K453, reminding of the machine being detained at the red signal - the machine still hadn't caused any track circuit occupation so the signal had stayed resolutely at red, and so the signalman had to verbally authorise the machine to pass the signal at Danger, to get it under way again.

Finally we thought, no more problems.
Wrong! The machine got as far as automatic signal K633, the first signal on the Down Slow after that line re-commences at Woolmer Green; - where it stopped :
For complex reasons involved with the Woolmer Green 70mph Down Main to Down Slow divergence being signalled using flashing yellow signal aspects on the two signals leading to the 'junction' signal, and K633, despite being an 'Automatic', was also released from red by track circuits being occupied on the approach to the 'junction' signal.
And of course, the 'Tracgopher' machine had not operated those track circuits, so K633 stayed at red !

So, once again the Driver of the machine had to be authorised to pass a red signal, and proceed on its way.

Thankfully there were no other problems in dealing with this machine; it's driver correctly reported in that it had arrived north of the trailng points from Down Slow to Down Yard at Hitchin, so that the signalman could cancel the routes behind it and set for it to go into the yard, and again that it was in the yard clear of the points.

But, as far as I noticed, (and with each problem, I tried even harder to carefully watch throughout for evidence of the machine's progress) I never saw the machine show up on the panel even once, and none of the signalmen mentioned seeing it.

The whole thing was a strange experience, knowing that this machine came onto our patch and 'invisibly' went all that way - about 28 miles - without apparently being seen : - A clear case for complying completely with the "... machines not guaranteed to operate track circuits." instructions !

On-Track Machines tend to be a lot larger these days, but I don't know that they are all 'guaranteed', so maybe the 'not guaranteed....' instructions are still in force and might still need to be applied.

[Bryan]

For the uninitiated I have attached a photo of our Gopher on the NYMR.
Here just returning after a spell on the Severn Valley.
Basically it works by dropping the digging wheel down in to 1 side of the track, (It can work to either side by use of the built in turntable but can only work in one direction.) Then when sufficient length has been dug out a chainsaw type affair only a lot larger is lowered into the trench and swung under the track. This then removes all the material under the track and deposits into the bucket wheel which in turn transfers it to the conveyor belt for disposal to wagon or bank.

It is not a Ballast Cleaner it can only extract material.
Often used to be employed for excavating through pointwork or for track lowerings.
The last time I worked with one on the big railway was at Monkwearmouth station in the early mid 90s when we reballasted the crossover and turn out to the colliery. Which promptly closed about a week later. I had to apply for listed building consent to Demolish about 6ft of the ramp end of the old station platform. Still identifiable now.

The Gopher that worked at Monkwearmouth was based at Leeds Holbeck at the time and ran up to Sunderland under its own power taking 2 nights to get there. I think it stopped at Northallerton the first night.

A newer version was used for reballasting Ferrybridge junction in 2006.

[StevieG]

Sounds quite ingenious for its age, Bryan.
Thanks very much for the photo. I now know the machine a little better, and it looks like my impression of its slightly diminutive size wasn't far out!