I am not an expert on this subject.

Most trains that I have seen have had the rear pantograph in use. In some cases, the front pantograph is used to prevent damage from sparks and small pieces of heated carbon (from the wiper) from damaging the first few cars or coaches trailing behind it.
This is especially the case with (new) auto carriers, petroleum and other flammable material.
I remember reading something about it being more common for loks to run with both pantos raised when the catenary is DC rather than AC, so this is likely more common in France and Italy to name a few countries using primarily DC power.

Regards

Mike C

There is always something to learn to this forum.

In Europe you can find 15,000 and 25,000 Volt AC - one pantograph is normally sufficient to feed a train.

And you find 1,500 and 3,000 Volt DC, too. I've heard that it's common in the DC world to start with both pantographs and lower one when the train has reached a certain speed.

A loco can take 600 Amps in Germany.
To get the same power in the Netherlands it needs 6,000 Amps.

Look here:
https://www.marklin-user...erms=raise,catenary,rear

It looks familiar to me that a loc will start with two pantographs up and lowering the front one after having acquired some speed.
Regards, Henk

Hi.

some days ago I talked on this subject with a friend who is a train driver. He told more or less what you say, but there is something to add.

DC operations is more complex because as you say there are greater currents involved.
This means also that catenary is bigger, but, and this is the problem, it is much more fragile!
So you at the same moment need more current, but travelling with 2 pantographs up means that the rear one is involved in oscillations in catenary caused by the front one and it can easily break or rip the catenary.
For this reason trains that need a great amount of current starts with both pantographs up and lower them at a certain speed, when it could be dangerous to have both them up.
In Italy, for what I know this is done at every stop with ETR500, the high speed trains. Maybe also for heavy goods trains.
I heard that this problem is even greater in France, because voltage is 1500V instead of 3000V.

Some multipurpose locos have different pantographs, and the "wrong" ones can be used only at speeds up to 20 Km/h. This is another reason why at a certain speed it is lowered.

In addition there are other problems that "common" passengers don't notice. In Italy there are two kind of 3000V catenary. One needsthe contact shoe in copper and the other one needs the contact shoe in graphite.
In some regions all the catenaries are the same kind, and the loco can travel with front or rear pantograph up without problems.
But in other regions, locos have a pantograph in copper and one in graphite, and they lift obviously the one required by the line they're running on. The "wrong" one can be used at low speed.

Pietro

I seem to remember reading a study a few years back about how the vibrations when using 2 loks affected the catenary wire. I recall that there was some mention of greater spacing between pantographs minimized the sway of the catenary that was caused by the passage of the lok (and it's slider). I wonder if this is also true in model RR?

Regards

Mike C

It is more to do with the resonant frequency of the wire. The larger the gap though the lower the frequency which means the the "springs" in the pantographs can move quickly enough to stay touching the wire. Doesnt really apply to MRR as arcing isnt an issue.

Not really. The front pantograph is raised if a loco, a control car, or sensitive freight (cars, explosives, wood) follows - even if the following loco has all pantographs lowered.
This applies to Germany at least.

In France it is mainly to start the heavy trains from standstill under the DC current lines. (to avoid damaging the one Pantograph) Once the train is rolling the front Panto usually comes down.

I saw a great video recently where they retired the CC6500 depicting this exact start under 1500V.

Not more to add to all the replies, except that the choices made for various electrification systems in Europe were dictated by the stand of technology at the time the decision was made, the geographic conditions and energy supply available.(Coal vs. hydraulic, etc.)
France started with 1500V in the 1920's, but as technology evolved and allowed for AC powered locomotives, most of the post WW II electrification was made under 25kv, 50Hz.
In this case, traction motors were still the same as DC locos(i.e. series wound DC) but with on board rectifiers (at first Mercury vapor, then later solid state)
For example the 1.5 KV DC SNCF BB 9200 (Marklin 3038) was basically slightly modified with a tranformer and a set of high power rectifiers to prodice the 25kV 50Hz BB 16000 series, practically undistinguishable from each other, except for the pantograph.
A third variation of the same design was the BB 25000 series, which were the first dual system high speed locos, basically mixing the components of both the precursor series.
I would venture to say that if Germany had these components available in the early 1900's, they would have probably never needed 16 2/3 Hz.
Today all locos have basically the same traction system using asynchronous 3-phase current, generated on board by a solid state giant power generator, which is either fed DC directly from thr catenary, or AC via a transformer and a set of fixed rectifiers, or derives its supply from a diesel driven generator.
All made possible by the fantastic developments in solid state power electronics.
Hope you find the info helpful