So how does a canal boat travel uphill?

Canal boats on the Grand Union Canal near Watford. Image: Roger Kidd/creative commons.

Sea-faring boats face many challenges, but uphills are not one of them. They have to deal with up-waves, of course, but that’s mostly easy because they just have to float and not flip over, which is a pretty low bar to set for a boat. Unique to canal boats is the need to drastically change elevation.

Coal-carrying boats, the original users of many of the UK’s canals, had to travel from the high coal-rich hinterlands down to the city and back again to keep the city dwellers warm and the factory fires burning. The altitude difference involved in doing so is pretty huge across the UK with the highest canal, Huddersfield Narrow at 654ft contiguously connected to waterways below sea level.

A canal is essentially a very long, very thin lake, meaning any incline will cause water to do its thing: flow downhill and flood the lower reaches. So, instead, different kinds of locks are used to lift boats from one level to the next.

While this works well when dealing with small inclines, locks can’t be too deep because each use would waste too much water. The alternative is what’s called a ‘lock flight’, which is essentially a staircase of locks that can be insanely time consuming to traverse. The Tardebigge Flight in Worcestershire, the longest in the UK, raises the waterway by 220 feet over the course of 30 locks. It takes an experienced crew a whopping four hours to navigate.

So boat lifts are the final piece in this weird puzzle. These are just what you imagine: a way of taking a boat, and the section of canal it’s on, from one level to the next. Lifts have the advantage of being far faster to use than lock flights, while also wasting much less water. Funnily enough the precursors to these feats of modern engineering far predate the relatively simple locks – the ancient Egyptians used crude lifts to get boats round waterfalls on the Nile.

 

The Falkirk Wheel connects the Forth and Clyde Canal with the Union Canal. Credit: Wikipedia/creative commons.

As is the case for most triumphs of engineering, Victorian Britain led the way. The Anderton Boat Lift in Cheshire has been taking water traffic the 50ft between the River Weaver and the Trent and Mersey Canal since its construction in 1875. Far grander boat lifts have since been built in other parts of the world, but little-Englander-waterway-enthusiast types can hang onto the fact the UK got there first. The most impressive modern example is the lift that gets ships over China’s Three Gorge Dam, which is simultaneously the highest and most powerful in world. Not nearly the same size but at least closer to home, the Falkirk Wheel in Scotland is incredible for looking like something out of Star Trek whilst still being a fully functional lift.

So that’s the briefest of outlines for all your boat-raising queries. If want to get more technical, try to wrap your head around the hydraulic systems beneath boat lifts such as Canada’s Peterborough Lift Lock. But if you really want a challenge try to square in your head how it can be that each lift weighs the same whether a boat is in it or not. It times like this I wish I had a bath; not for cleanliness’ sake but to conduct experiments with my rubber ducks. 


 

 
 
 
 

What's actually in the UK government’s bailout package for Transport for London?

Wood Green Underground station, north London. Image: Getty.

On 14 May, hours before London’s transport authority ran out of money, the British government agreed to a financial rescue package. Many details of that bailout – its size, the fact it was roughly two-thirds cash and one-third loan, many conditions attached – have been known about for weeks. 

But the information was filtered through spokespeople, because the exact terms of the deal had not been published. This was clearly a source of frustration for London’s mayor Sadiq Khan, who stood to take the political heat for some of the ensuing cuts (to free travel for the old or young, say), but had no way of backing up his contention that the British government made him do it.

That changed Tuesday when Transport for London published this month's board papers, which include a copy of the letter in which transport secretary Grant Shapps sets out the exact terms of the bailout deal. You can read the whole thing here, if you’re so minded, but here are the three big things revealed in the new disclosure.

Firstly, there’s some flexibility in the size of the deal. The bailout was reported to be worth £1.6 billion, significantly less than the £1.9 billion that TfL wanted. In his letter, Shapps spells it out: “To the extent that the actual funding shortfall is greater or lesser than £1.6bn then the amount of Extraordinary Grant and TfL borrowing will increase pro rata, up to a maximum of £1.9bn in aggregate or reduce pro rata accordingly”. 

To put that in English, London’s transport network will not be grinding to a halt because the government didn’t believe TfL about how much money it would need. Up to a point, the money will be available without further negotiations.

The second big takeaway from these board papers is that negotiations will be going on anyway. This bail out is meant to keep TfL rolling until 17 October; but because the agency gets around three-quarters of its revenues from fares, and because the pandemic means fares are likely to be depressed for the foreseeable future, it’s not clear what is meant to happen after that. Social distancing, the board papers note, means that the network will only be able to handle 13 to 20% of normal passenger numbers, even when every service is running.


Shapps’ letter doesn’t answer this question, but it does at least give a sense of when an answer may be forthcoming. It promises “an immediate and broad ranging government-led review of TfL’s future financial position and future financial structure”, which will publish detailed recommendations by the end of August. That will take in fares, operating efficiencies, capital expenditure, “the current fiscal devolution arrangements” – basically, everything. 

The third thing we leaned from that letter is that, to the first approximation, every change to London’s transport policy that is now being rushed through was an explicit condition of this deal. Segregated cycle lanes, pavement extensions and road closures? All in there. So are the suspension of free travel for people under 18, or free peak-hours travel for those over 60. So are increases in the level of the congestion charge.

Many of these changes may be unpopular, but we now know they are not being embraced by London’s mayor entirely on their own merit: They’re being pushed by the Department of Transport as a condition of receiving the bailout. No wonder Khan was miffed that the latter hadn’t been published.

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