themiller
Member
I’ve just checked some photos of the LNER EF1 locos underway and all show 2 pantographs up and, in one photo, you can see twin conductor wires.
They are also suburban units with a relatively low maximum speed (140km/h), so are unlikely to disturb the OLE stability too much. Apart from the fact that they only have motors in the end cars per unit so that a 16kV line doen't need to pass through the trailers, they functionally have a similar traction supply configuration to the UK classes 345 and 700.SBB's RABe514s operate with two raised pantographs. The two halves of the train are not electrically connected on the high-voltage side. With four units, 8 pantographs are then lifted. However, they normally run with a maximum of three units.
It was used so DC motors could run on it without rectification, however at 50Hz the arcing between brushes and commutator was unacceptable but was within an acceptable limit at 16.7Hz.That's what I've heard as well. 16 ⅔ Hz was chosen as a compromise that would work fine, the motors could run on it and the voltage could be reduced onboard. Early railway electrification in Sweden actually used 15 Hz, but the frequency was later increased to 16 ⅔ Hz.
That's why you in general see 25 kV 50 Hz in countries that started electrifying late. Like Finland (1960s), Denmark (1980s), Portugal (1950s) or the UK.
https://www.railwaysarchive.co.uk/documents/MetroVickers_MSWLocos1954.pdf may be a good startInteresting, I wonder if the electrical schematics for those locos still exist somewhere.
Though, if you are old enough, that might have been two slightly wider-spaced contact wires for the 3 phase AC lines in the north of Italy using two current collectors side by side. They were subsequently converted to DC. There was a short line 3 phase freight operation in Spain down to Almeria but it was no longer electric when I tried to find it in 1974.Just to add a bit about two contact wires being used, have often seen that on 3000V lines as well. Definitely seen it in Italy ...
No, I'm not that old!!! First went to Italy in 2002 and only started doing trains there in 2015 so definitely standard 3000V! Looking through few pictures I have from this year, twin wire in Taranto and Firenze Rifredi.Though, if you are old enough, that might have been two slightly wider-spaced contact wires for the 3 phase AC lines in the north of Italy using two current collectors side by side. They were subsequently converted to DC. There was a short line 3 phase freight operation in Spain down to Almeria but it was no longer electric when I tried to find it in 1974.
dispite being same family as the NS locomotives suprising they have a diffrent pantograph layout (NS ones point either direction while SNCF one here has them facing same direction)SNCF locos thus fitted commonly raise both pantographs at slower speeds / starting a heavy train from a stand - even on bi-voltage locos where one of the two pantographs is supposed to be for ac and one for dc.
As an example here is a (though I say it myself) a rather superb shot I took at Beaune in June 2022. Both locos are bi-current 22200s
The 22200s have them both in same direction (and either can be used for dc or ac operation) whereas 7200s have them in opposite directions, similar to NS 1600s and 1700s. Think 15000s only have one pantograph but happy to be corrected on this one.dispite being same family as the NS locomotives suprising they have a diffrent pantograph layout (NS ones point either direction while SNCF one here has them facing same direction)
Which makes sense as the prototype locomotive for the SNCF BB 7200 also was the prototype for the NS 1600s. With that French prototype various trials have been done in the Netherlands which after some small adaptions resulted in the order for the class 1600.whereas 7200s have them in opposite directions, similar to NS 1600s and 1700s.
Think 15000s only have one pantograph but happy to be corrected on this one.
similarly, cc6500 + cc14500 = cc2100015000 (ac) + 7200 (dc) = 22200 (dual)
And also...similarly, cc6500 + cc14500 = cc21000
But the cc14000 remained a project and never materialized.
Also BB9200+BB16000=BB25200similarly, cc6500 + cc14500 = cc21000
But the cc14000 remained a project and never materialized.