Return to High Barnet by Northern Line

Thinking that my experience of Northern Line automatic operation described in my 2 July blog might be unrepresentative, I found an excuse to visit High Barnet again (it wasn’t a very good excuse, but I did it anyway). I entrained at Archway and on wandering into the station checked to see that the ‘wisdom of the day’ notice was on display in the ticket hall – it was, and it has been there each time I’ve been through and I rather like this kind of individualism, so often suppressed by dull bureaucracies determined to eliminate any kind of personalization. It has to be done well, and it is at Archway, and I dare say it is hard work keeping up the standard. Long may it continue; stations are personal to their users, and they like it.

Reluctantly, I descended from the sunshine into the dark bowels of the station to inspect the train service along what is now an automatic railway, to the north. In summary, my feelings were pretty much the same as last time with the one difference that top speeds were a bit higher. I can only conclude that the train control system (a system matching speed and train despatch to the timetable) had decided to dampen down top speeds on my previous visit to meet some kind of service requirement.

On this latest visit I was armed with a stopwatch and measured some speeds. On the whole, the train generally attempted top speed between stations, which, as indicated last time, is 45 mph north of East Finchley. There were oddities. Between Highgate and East Finchley (max speed 40 mph) we certainly achieved 40 mph briefly, but unaccountably, about half way up the gradient, slowed down a noticeable amount then accelerated to 40 mph again. Why? Nothing in front. North of East Finchley we stuck on about 30 mph for about a third of the way to Finchley Central before suddenly accelerating to line speed, but then began slowing curiously early. The curve north of the station was managed down to 25 mph, a painfully slow speed for such a long distance (and with the usual stop-start of power being applied). The electronics was applying huge precision to what in my view are at least questionable and, quite probably, arbitrary limits. I cannot blame the signal engineers for this but as a ‘system’ I think we can do better.

On the southbound run into Highgate (with the repetitive slowing down) I could hear the constant wheeze of brakes being applied in concert with the obvious sensation of braking, but it was air braking. Surely this is just the occasion where regenerative brakes ought to be at work, making good use of the recovered energy and providing a constant braking force rather that the annoying swaying effect? No doubt there is an explanation, but let us hope this is also something that will be sorted during the upgrade.

Other than that, the trains still exhibited the overly-aggressive motoring/speed-checking behaviour (swaying); I accept that there must be a top speed, but with modern electronics and precise knowledge of train position we should be managing top speed by balancing power input against train drag at the desired speed (the 21st century approach), not turning full power on and off to get a crude average which is how engineers did it a hundred years ago. I assume that this will eventually be fixed by a software upgrade. Maybe this kind of teething problem is unavoidable, but I’m not sure I understand why the need for a comfortable ride cannot be picked up earlier in the process. Maybe I seek perfection? And what is wrong with that then?

On the subject of perfection there was an interesting event on the evening of Monday 8th July when (if the RMT be believed) two trains met head on between Finchley Central and Mill Hill East and one reversed smartly back to Finchley, averting certain disaster. That, at least, was the tenor of the report! Now, having once found myself dealing with an alleged signal irregularity on the Victoria Line of at least equally profound significance (line-closing stuff unless a certain degree of proportion is adopted), the report sounded a tad selective. Informed sources suggest that there was no safety-critical incident (ie no danger) but it was discovered that two trains in opposing directions could be fired off against each other on a single line by what I call the train despatch system. Personally I have absolute faith that (as in my own incident) the train protection systems would have stopped the trains had not someone noticed something amiss and stepped in sooner.

The moves would I think have been possible under the old signalling, with trains bought to rest near the junction with the single line until a non conflicting route had been identified for the southbound train. It looks as though the train signalling processors have not been programmed to warn against trying to set up mutually exclusive routes before wheels were allowed to turn. I gather there is a similar issue at Neasden north on the Jubilee Line where it is possible to signal trains into the underpass from opposing directions. Not unsafe (signalling will prevent any collision), but not something that will help the service along as one train must, perforce, give way. When humans were entirely in control there was only one controlling mind. With humans doing certain things and computers doing other thing it looks like we need a new way of getting along with each other!

Having got to Barnet, there was nothing to keep me there, even on a warm summer’s evening, and the place had changed since my day. It was much busier, for a start. The station manager’s tea was usually worth dropping in for, and an opportunity to pick up gossip at this sleepy backwater. It was a crew depot, but not in such numbers that it left any impression of being busy in any way. When an area manager the only exciting thing that caused me to go up there in a hurry was a report from a guard of a very loud bang as his train left Oval, and the train stabled at Barnet. I thought it worth going along myself and eventually decided to check the roof, climbing up between the cars to get a look (not easy at it was about midnight and very dark). There was a huge dent in the leading end. This matched damage to the portal at Oval. Discussions with rolling stock and p’way suggested the clearances were ‘tight’ and combined with the drop in gradient at the platform end meant that a car that was within gauge when stationary might not be when travelling at 30 mph. The answer was a 25 mph speed limit and living with a clearance of millimetres (the car was probably at its high end of height tolerance anyway). I’ve not heard of any other incident there and wonder if the dent ever got fixed.

Changes at Barnet include new signs and lighting and a (very long and bendy) walkway around the buffer stops providing level access to platforms 2 and 3. There was also a new staff footbridge at the south end, leading to large modern buildings quite out of keeping with the rustic 1860s station: traincew accommodation, no doubt. Necessary changes, I am sure, but signs of progress that just seem a little out of keeping with the place. Suspecting it might be me that was out of keeping with the place, I took my stopwatch and fled!


Advertisements

About machorne

I have always lived in London and taken a great interest in its history and ongoing development. This extended into the history of its transport services, about which I have written a number of books - I have spent most of my working life working in the industry and observing changes from within, mostly to the good, but not always so. I continue to write, and have a website with half finished stuff in it so that it is at least available, if not complete. Several new books are in hand. I have many 'works in progress' and some of these can be found on my website; the we address is http://www.metadyne.co.uk
This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s