Multi-System Trains

[AdamWW]

There are some routes in Spain where dual gauge 1668 and 1435 mm track is, and is being, laid, these have the usual three 'pads' for the rails so you have one common rail, one 1435 gauge rail and one 1668 gauge rail. The main places to see these are on the freight routes around Barcelona (which connect into the standard gauge high speed line into France) and out of Valencia towards Castello de la Plana; these will eventually be connected up to give Valencia a standard gauge route to France.

To add to your comprehensive summary, I believe that on the opposite coast the line from the French border at Hendaye/Irun is being dual gauged to give more scope for standard gauge freight (and also a tunnel was enlarged to increase the loading gauge - while keeping the tunnel in use which is quite a trick).

high speed services from Madrid to Salamanca run along the high speed line via Segovia to Medina del Campo AV, then turn off through the gauge changer there, then stay on 25 kV to Salamanca.

Yes - I did that recently and it was odd not seeing signs for an electrification change along with the gauge change.

As an aisde, I didn't find it a terribly interesting journey. The "classic" line to Madrid was quite a bit slower but had much better scenery. (And a less full train so I could move to whichever side had the best views).

 

[FormerBritInMe]

And there is increasing standardisation towards the standard gauge track gauge, in that both the Baltic States and Spain are building new lines with the standard gauge. Similarly, there is a move towards 25kV AC (50Hz), with new lines across almost all of Europe following this.

Although Rail Baltica is standard (1435mm) gauge, I suspect that the legacy lines will remain Russian Gauge (1520mm) for the foreseeable future, as will the lines in the former countries of the Soviet Union.

Here in the US for historical reasons we ended up with 3 systems on the Northeast Corridor. The New Haven Railroad pioneered high voltage AC electrification with its 11 KV, 25 Hz OLE New York to New Haven. That was adopted by the Pennsylvania Railroad in electrifying New York to Washington and Philadelphia to Harrisburg PA. After New York State's Metro North and the State of Connecticut took over the former New Haven trackage it was upgraded to 12.5 KV 60 HZ. I assume they elected to use 12.5 KV rather than 25 KV due to the use of the existing catenary structure and clearances that had been built for 11 KV. Then in the 1990's Amtrak electrified New Haven to Boston at 25 KV 60 Hz. All of the Amtrak locomotives are designed to handle all 3 systems. Some suburban MU equipment is more limited, for example Metro North's EMUs used on the New Haven line cannot run on 25 HZ.

There is sometimes talk about why the whole system isn't upgraded to 60 Hz, mostly in the railfan community but no serious proposals have been made to change this. Much of the electrical supply infrastructure has been upgraded e.g. solid state frequency converters. Also a significant percentage of the power is from 25 HZ water turbines in the Susquehanna River dams. Right now the biggest issue is upgrading the OLE itself which needs constant tension to allow higher speeds and reduce issues with both high and low temperatures. As usual, funding is in short supply.