[Mike B]

It's not just a European thing. In U.S. interurbans there were several cases where voltage switches, and even changes from overhead to 3rd rail, were done (see: Sacramento Northern). For instance, a 1200V main line entered a city with 600V wires; if the train didn't stop to operate a changeover switch, it would run at half speed with dim lights. Sometimes, dropping the pantograph and changing to trolley pole would also switch voltages. Then there were the systems with inadequate power supply (SF Muni in the 1950s-60s comes to mind, in the downtown area) where line voltage would sag significantly at commute times with heavy loads; the nominal 600V power could drop below 300V, but the old-style PCCs just kept moving if a bit slowly and with dim lights.

A small tweak might be to add something to differentiate between modern and "vintage" electrics under those circumstances. Modern electrics, if designed for dual-voltage, might automatically change over so except for operating details (like having power off at the change point) it wouldn't be noticed; with some older electrics, it was necessary to stop and operate an external changeover switch. In the case of voltage sags, a modern vehicle would likely just stop - because of the computers and such they often just don't work if voltage goes outside the normal range, while the older stuff can struggle along with much-reduced performance. Interestingly, I've been on some all-electric (no air brakes) LRVs where everything dropped off line, but the train kept coasting; perhaps braking is an issue in those cases?

I think the dual-power (not dual-voltage) case has been discussed before; that also would be nice to model for the New York area, which is the only place where that's presently done in the US. NJT has dual-power diesel and overhead wire (recent model only); LIRR, Connecticut, and Metro North have done diesel + 3rd rail for ages (Remember FL9's? Also P32DMs and whatever that boxcab thing is that LIRR uses?). While not the same thing as the dual-voltage scheme, it's similar. In MSTS, you can't make the change on the fly, either. Have to drive (for instance) on diesel into electric territory and stop, exit the activity, and start up a new activity from that spot using the electric .eng file.

Interesting idea. Worth adding as OR goes beyond basic MSTS compatibility.

[RTP]

The Spanish Alvia, can work with 25000AC, 1500DC and diesel, with three very diferent physics.
Will be very nice simulate that.

Regards.

[DRelyea]

Hi,

To pile on, the L&WV was forced by the City of Wilkes-Barre to operate with overhead wire within it's city limits. Elsewhere the L&WV was a third rail operation. (Lackawanna & Wyoming Valley, or the Laurel Line)

Doug Relyea

[EricF]

There were also the New Haven FL9s which could run from diesel power or switch to 3rd rail electric.

There are quite a number of multi-power locomotives around the world. For some, operating characteristics may not change much from one power mode to another but in others there may be significant differences. At the very least, there's an operational procedure to change from one power source to another of varying complexity. That in itself could be interesting to simulate. Probably not a version 1.x line of development, but perhaps for the 2.x roadmap?