GOOD NEWS: the Gospel Oak to Barking line is about to get a major upgrade.
BAD NEWS: large parts of the line will be out of action until early 2018.
The Overground route, affectionately abbreviated to the GOBLIN line, is something of an anachronism in London. Its two-car trains still shunt back and forth on diesel. The £133m investment will not only electrify the line, but also double capacity with the introduction of four-car walk-through trains.
The price we have to pay is significant closures to the line, which should look like this:
4 June to 26 September 2016: there will be no rail service whatsoever between South Tottenham and Barking. Services will run from Gospel Oak to South Tottenham during weekdays, but not at weekends.
26 September to sometime in February 2017: the line will be totally closed over its full length, on weekdays and weekends. It will then reopen in early February.
March-June 2017: regular closures at weekends and evenings for testing.
Early 2018: New four-car electric trains enter service.
The conversion of the line requires more engineering work than you might imagine. All the kit needed for electrification must be installed. Tracks will be lowered at several locations, and four bridges must be replaced. Platforms must be extended to allow four-car trains. For a slick overview of the works, watch this Network Rail video.
The closures are obviously going to affect a lot of people. Replacement buses will operate along much of the route, but we all know how annoying they can be.
Those seeking alternative routes may have concerns that they'd have to dip in and out of zone 1, raising the cost of a journey that would normally stick to zones 2, 3 and 4. According to TfL, "regular pay as you go users of the Gospel Oak to Barking line will be automatically refunded the additional cost of travel via zone 1 by tube or rail". That word 'regular' is defined as at least three times a week. More casual than that, and you'll have to pay the full fare — as will travelcard holders.
For more details on the closures, see TfL's website.