People use Metrolink BECAUSE HEAVY RAIL HAS CLOSED DOWN AND THERE IS NO ALTERNATIVE. What about all the people who would like to use rail-based public transpirt but can't, bevause there's not enough space on Metrolink to carry them? Who is to say that, if Picc-Vic and the accompanying suburban railway improvements had gone ahead, the millions using Metrolink would not be using those systems instead, in line with the general upward trend in HR use?
Re Germany, statdbahn are modernised street tramways. The larger, more successful German cities - the ones ckmparable to Greater Manchester - have not followed the Manchester model of turning HR into LR. At most, a number of smaller German cities, many in the still-depressed east, have run extensions of LR services onto HR tracks (without kiboshing the latter for HR services, unlike Manchester). Conveniently for your argument, you omit the fact that 14 German conurbations have S bahn systems. Of course, some of them have tramways as well, but they're there to supplement HR services, not to substitute for them.
Similarly, I don't think anyone here argues that there is no place for light rail. In Metrolink's case, the airport, Eccles, Ashton and Trafford Park lines are useful ways of serving their respective areas. All of them, however, could be built without removing HR capacity.
Your argument is utterly contradictory. On the one hand, you argue that LR Iis required everywhere to avoid spending money on excess capacity. On the other, you acknowledged that LR no longer provides sufficient capacity in the city which has been the poster child for conversion of HR to LR, and that substantial extra spending is now required as a result.
The way to secure a viable future for public transport in this country is to provide proper services which encourage more people to use them, not to pander to politicians and civil servants who fundamentally hate non-private car users by providing token systems which can't carry the people who want to use them.
People don't have to use heavy rail. There are bus services, and people can drive. Buses run closer to where people are starting and finishing their journeys, while cars have maximum flexibility. For rail-based transportation to compete, it must be better at popular sorts of journeys than either option. Metrolink, by virtue of making an operational profit, is clearly doing so.
What did the Altrincham and Bury line timetables look like just before conversion? The number of seats on a train isn't the only story. The theoretical capability to run a high capacity service means nothing if operational and economic concerns limit it. If you turned up at Altrincham in 1990, how long did you have to wait before you could catch a train to Manchester? Today, you have to wait only about 3 minutes on average.
Have passenger numbers generally grown on Metrolink every year? If so, and there's not enough capacity today, wouldn't that mean that back in 1990, passenger numbers were lower? If there has been growth and it is now that there's not enough capacity (Metrolink frequency to Altrincham is restricted by the single-line section at Navigation Road), then clearly back then there was enough capacity. If there was enough capacity back then, and passenger numbers hadn't fallen off a cliff when conversion happened, then the number of people using HR services was also low back then. When passenger numbers are low, the immense cost of a tunnelled metro line is not justified. When passenger numbers are high, it becomes more justified. Metrolink has caused passenger numbers to increase above and beyond what was possible with any other sort of system, thereby making a tunnel more essential and worthwhile in future.
Again, you cannot simply compare population figures to justify transport decisions. German cities of the same population as UK ones tend to be far more compact as they didn't see so much suburban sprawl. We would be more comparable to Germany if we had decided not to build the New Towns and instead rejuvenated medium-density areas. Without significant areas of medium density, you simply cannot justify the cost of tunnelling. Indeed, it's also harder to justify even a street-running tram system. Of the tram systems in the UK, only Sheffield, Edinburgh(*) and the latter extensions of Manchester Metrolink are not focussed on taking over rail alignments. When you've got a rail alignment to re-use, lower density isn't so much of a problem as the infrastructure cost per kilometre drops significantly.
(*) The only line yet built in Edinburgh spends most of its time following the E&G. However, the system was designed primarily to serve Leith Walk and running down to the BioQuarter along the streets.
Larger cities will have more space on the transport spectrum for independent systems to exist. Megacities like London and Paris can easily justify everything from buses to heavy rail metros existing alongside one another, as they individually have more than enough demand to be economically viable. Smaller cities don't leave so much space on the spectrum, making it more likely for the systems to address multiple needs. Using Leipzig as an example, the new S-Bahn tunnel exists alongside a dense tram network but leaving little space for an U-Bahn to be necessary in between. The sorts of journeys that would be done on an U-Bahn in a larger city get split between tram and S-Bahn so that there isn't massive duplication of resources while all journey requirements still get addressed.
In Cardiff, the problem you've got is that the population and density isn't high enough right now for a tram network to exist alongside a heavier rail network and buses. The only way of making a separated tram system viable would be to take enough passengers off heavy rail for heavy rail to become unviable. Therefore, if we're to address transport needs that aren't served by heavy rail, we have to look at changing the nature of the existing heavy rail system so that it can scale down to these needs without losing out on demand at the upper end.
As I repeatedly say, LR technology is by far the most flexible of any rail-based transport mode, as you can pretty much use any sort of line you want. If you really need to have a segregated line, you can run it with the same trains and using the same technology but without ever ending up running on the streets. This is what happens on the RandstadRail network designed by those most public transport-friendly of peoples, the Dutch. Using T&W Metro-style through running you can have a light metro take over existing HR routes without requiring those tracks to be converted.
What the Metrolink conversion of the Altrincham and Bury lines has done in Manchester is provide the framework required for the other pure street running lines to be built. The lines to Eccles, the Airport and Ashton would simply not have happened if Metrolink hadn't built the expensive street running core in the city centre. The densities along these lines are simply not high enough for them to justify all the infrastructure they would need, but they are high enough to justify it if something else paid for the most expensive fixed costs. When these lines were built, the fixed costs of providing depots and city centre street running and operational control centres and ticketing systems and so on had already been paid. The bigger the network gets, the less significant these costs become. Once a line is built, urban development adjusts to suit and densities naturally become higher. Now that Metrolink exists, there's much, much more interest in building medium-density urban environments along these lines. As these develop, they increase passenger numbers. Before long, the pure street running Metrolink lines will have enough passenger demand to justify their own existence. They'll no longer need the converted HR lines as scaffolding. There'll be more space along the spectrum for independent transport systems to co-exist.
What many think/fear will happen is a LR service from the tops of the Valleys running to Cardiff Queen Street where all passengers would be forced to change (or more likely walk to Central) to get a train to the rest of the current local or main line network.
The example used was LR to Kidderminster and then an HR shuttle to Worcester. That's the Merseyrail example, and it means people have to change trains essentially at the edge of the suburbs. Cardiff Queen Street is not at the edge of the suburbs. It's about as far from the shopping area as Central.
I don't believe we're going to see a mass service split at Queen Street, because doing that would be operationally inconvenient for the transport operator more than anything else. At most any extra services running up the Valleys on top of today's service would run onto the streets or down to the Bay, but a split would require actual extra infrastructure spend for no obvious benefit. The people saying there has to be a split are the people saying that NR are going to say no to a HR-standards-compliant LR train running on their metals, or that HM Treasury is going to push for guards and HR costs to be retained in perpetuity in Wales rather than paying a small extra capital sum and getting rid of them forever.
