Track Wear & possible solutions

The issue runs wider than just the Central - and perhaps the right place for this thread is in Signalling and Track?

Inherently the curvy nature of many tube lines is largely a legacy of minimising property owners compensation claims during their initial construction by keeping most of the tunnelling under existing streets. The cost and disruption of trying to straighten out even just the most severe locations is huge especially for an intensely worked line like the Central line.

Over the years the corollary of bendy tracks and enhanced track and rolling stock wear is well known. Various ideas have been explored to reduce the overall cost - For instance I vaguely recall seeing pictures of a semi articulated 38 stock. Inherently whilst the physical space for a bogie remains little changed, the scope for radical change is limited as most modern stock has lots more going on within a typical bogie than just supporting the carriage weight. More wheels tend to be driven, all tend to be braked, most have some sort of suspension/damping, many also carry masses of cabling for power collection and regeneration, wheel slip protection and other sensors. Which is great when they all work well, but the more you jam into the same physical space the harder it is to maintain (for instance changing braking surfaces) and keep all this stuff in good order.

Inherently rolling stock suppliers have invested heavily to improve bogie and axle designs over the year and inherently make their product best suited to the majority of their customers needs. However that historical legacy means that London tube lines are probably at the most extreme end in terms of customer requirements. Inevitably developing a bespoke design to ideally suit just a handful of lines with very infrequent orders, would be a huge gamble for any manufacturer to take especially in a competitive market where they have no certainty for orders, and cost rather than quality seems to be ranked far too highly in the purchasing department.

In pure competence terms, I feel sure manufacturers could still build stuff to robust IKB(Isambard Kingdom Brunel)standards. Sadly the current political environment is increasingly headline focused, and set against a fares freeze background, there is no real prospect the funds will be found to invest in that sort of development to deliver quality which would last and last.

I wonder if there is anything to be learned from the world of trams, where very tight radius curves and constrained space are commonplace?

Looking at the rail layout, i wonder why the tram didn't go straight on across the diamond?

I too have often wondered why a single-slip wasn't installed here. I can't think of a location on Metrolink with one though so my thinking is that they just wanted to stick to what they know and use simple pointwork.

Edit to add:



An interesting point, but look closely and you'll see that the above is laid with traditional rail, converting to tramway rail behind the tram. I'm not sure how a tram running on its flanges would cause more squeal as if anything there is less interaction between flange and rail.

stapler , Judging by date @edgarpulik gave, it would be Channel 5's Inside the Tube: Going Underground Episode 2 - The History Of The Central Line which was last broadcast on 20/11/17.

How did Trevithick get on with his Catch-me-who-can and its circular track?

The fact that the wheels are mounted fixed on axles will cause wear, no matter what lateral forces occur. If a train traverses a 90 degree bend, the outer wheels will travel about 8 feet further than the inner wheel (assuming standard gauge) so there must be some slip. Obviously the effect will be greater the smaller the radius of the bend.