Here we go again. Heidi Alexander, the former Lewisham MP who recently quit to take a new job as London’s deputy mayor for transport, has given a speech demanding that Transport for London (TfL) be allowed to take over the London-y bits of the Govia Thameslink Railway franchise.

Here’s the key quote:

“The crisis with Govia Thameslink is blighting the lives of Londoners, and risks causing our city economic damage if it continues much longer. Transport for London’s record of running successful rail services in the capital shows that giving it control of GTR’s beleaguered routes out of Moorgate is a no-brainer....”

TfL stands ready and willing to take over the struggling franchise as soon as 2020, she said. She went on:

“We also stand ready to take over West London Line services between Clapham Junction and Willesden Junction, but our ambition doesn’t stop there – metro services across Southern, SouthWestern and SouthEastern should be our goal.”

The idea that TfL should gradually absorb the city’s various suburban mainline railway services isn’t a new one. London Overground has been growing steadily since its launch in 2007, and the idea that TfL should run more routes has had support from every mayor since Ken Livingstone. The main barrier so far has been the naked partisanship of the transport secretary Chris Grayling – and even though he’s displayed a superhuman ability to survive gaffes that must be the envy of most normal politicians, then logic suggests he will still go away some time.

In 2016, indeed, TfL even published this map of its ultimate ambitions:

Click to expand. If you want to see a really big version, expand it, right click and open the image in a new tab.

All the same, I’m not getting too excited about Alexander’s speech, for three reasons.

One is that, while Grayling is undoubtedly mortal, he is nonetheless likely to be the man who decides whether or not part of the solution to the GTR mess will involve passing a chunk of the network over to TfL. He’s made clear his opposition to such a move in the past, and there’s no reason to think that he’s changed his mind. (If I wanted to be mean I’d add that there’s no reason to imagine he even can change his mind.)

Another reason for wariness is more technical. Look again at the suburban rail map above, and you’ll note that one line on which TfL has no designs is Thameslink itself. That’s an odd exclusion in its way: if the service ever runs as intended – if – the central section, from Finsbury Park and Kentish Town through the City to London Bridge and Elephant & Castle, would make a helpful adjunct to the tube network.

So why doesn’t TfL want it? My guess is because it’s impossible to separate the long-distance and local services on the line, and TfL has no interest in running trains to Brighton or Peterborough.

But since the heart of GTR’s problem is Thameslink, it’s not clear to me that a solution that doesn’t involve Thameslink will magically make anything better. It probably will get better, because problems get solved and reversion to the mean is a thing, but it’s not obvious to me that TfL’s involvement would be the critical factor here.

Indeed, in some places – the Greenwich line, for one - I’m pretty sure that Alexandra’s plan would mean that Thameslink trains would literally be sharing tracks with London Overground ones. I guess this might work better than the status quo; but it if doesn’t, it might just mean that blame spreads from private train operating companies over to TfL.

There’s one more reason I’m suspicious of the deputy mayor’s plan. It’s that, despite what she implied in her speech, TfL actually already runs the West London line from Willesden Junction to Clapham Junction, and I’m a bit worried that the mayor’s office doesn’t know seem to know that.

All that said: TfL probably should run more of London’s rail network, and it seems unlikely it would do a worse job than GTR. I’m just not convinced the case for this is actually any stronger than it was six months ago.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.

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