New GO Train Control+Signalling (PTC, CBTC, ETC) -- Safety & Subway-Like Frequency

[MovingBlock]

It's on this basis that the original SelTrac signal system was designed, built and operated. If the Dutch have manged to port this to a heavy rail application, this is quite a big deal.

Dan

The original Seltrac system is based on LZB, which has been in use on mainlines in Austria, Germany & Spain since the 70s, and some metro systems in the German-speaking world. You can get 30tph with EMUs with LZB or ETCS L2 with very short blocks (as is done on the Munich S-bahn core section). The main benefit of using virtual sub-sections (proposed with the ETCS Hybrid L3 specification) versus fixed blocks is that you reduce the amount of track-based vacancy detection equipment you need.

Neither the Weston sub nor a fixed block subway system come anywhere near the frequency of movement authority updates of a moving block system.

The Dutch innovation is to use virtual blocks which exist purely within the digital realm (i.e. without any associated track circuits, axle counters or physical signals) as a subdivision of physical blocks which do exist with axle counters. It would be outrageously expensive to install that many physical signals and track circuits, and even if we did, it would be absurd to expect drivers to be able to read a new physical signal every five seconds along the line.

With LZB & ETCS Level 2, the movement authority is also transmitted directly to the cab at regular intervals, so there is no lineside signalling. There are also no minimum block length requirements for either LZB or ETCS L2. The difference with Moving Block is that with LZB & ETCS L2, there is no way to confirm the train's integrity (i.e. that the train hasn't broken apart), so they are completely reliant on track-based vacancy detection.