Electric Lok Questions & Answers

(1) In real world, I observe most of the eloks run with the front pantograph down and the rear one up. Is that because of aerodynamic considerations?

(Answer - Tom Orle, Joerg Bruehe, & Marout Yasuo Sluijter-Borms, Greg Proctor)

It has nothing to do with aerodynamics.

Pantographs have a graphite piece to make the contact with the catenary wire (so that the wire stays intact, and the wear is on the graphite which can easily be replaced). As the panto slides under the catenary it gives off sparks of melted carbon and metal. To prevent the resulting melted graphite dust from falling on the lok's roof the rear pantograph is used. The forward panto is normally used when piloting another lok or there is sensitive cargo immediately behind.

Normally the rear panto is used unless the loco, as noted above and below, is coupled to a tank car, another loco or a car transporter. The reasoning is as follows - if the front panto is up and somehow gets damaged while speeding along, the broken panto could damage the rear panto. But if the rear panto is used and gets damaged, then the loco can continue to the next stop using the front panto. A fault in the catenary could tear the pantograph. (Click on the underlined text to see a video of a damaged pantograph and what it does to the catenary.) If thee leading panto is damaged then it will probably catch the second panto and destroy it also, leaving the Lok without power. As catenary has become more robust this worry has diminished to the point where many Loks are only fitted with one panto.

But they don't use the rear panto when an automobile transporter is the first car behind the loco because the carbon deposits from the panto's wiper will dirty the automobiles.

If a flammable liquid or gas tank car follows the loco it becomes a safety issue. If the train is double headed, then the first loco will have the front one up and the second loco will use the rear unless the above mentioned cars are behind it.

Loks like E44, E93, E94 etc all ran with two pantos up because the technology of the carbon block panto sliders wasn't far enough advanced. In the 1950s/60s the technology advanced and new Loks were built where one panto was enough to collect the required current. The older Loks got upgrades when replacements were required.

Since the NL uses only 1500V DC, many locos and triebwagen use both pantos during shunting, to have greater area of contact when using heavy current to set in motion the vehicle.

The 1200 series used to automatically raise front panto upon station hold and lower it, once the train had reached low enough power consumption to enable single panto running.

Jens Wulf and others have shared links to e-loks with front pantos up, some with several loks and only one panto on the loks is up, and pictures with several pantos up. Go to the links below to see these pictures. These are followed by a youtube video of a panto and catenary being destroyed.

Both front pantos up on two loks:
Click here to see two front pantos up.
Only one front panto up but with two loks:
Click here to see one front panto.
Back to theme, but, still, one panto less up then expected - (front, front, none):
Click here to see two front pantos up on a triplet.
Here is the classic triplet with only the first front panto up - (front, none, none):
Click here to see one front panto up on a triplet.
Again front up, and none on loco number 2:
Click here to see one front panto.
Always two pantos:
Click here to see two loks one with both pantos up and the other two lok consist appears to have both front pantos up.
Click here to see two loks both with front pantos up.
Click here to see two front pantos up. Note the consist.
Click here to see two front pantos up on two loks and the rear panto up on the second lok.
Click here to see two front pantos up. Again, note the type of consist.
And last, as expected, front and rear ... wait a moment? front, none, none, rear??? rear?! oil bins!?
Click here to see one front panto up on first lok, none on the next two and the rear panto up on the fourth lok.

Iwan Blom's answer to a question whether there are cables between loks with no pantos up: "No, there are no cables. The DB loks use certain systems for double or multple heading. One of these systems is ZMS. ZMS is used on both 151 and 185, but 185 is not allowed use it when it's running with dissimilar loks. The 140 has a different system, hence the 185 and 140 are ballast here :-) They're probably be moved as a repositioning item."

Tom Torle further explains repositioning loks. "Me thinks they are just along for the ride as in a repositioning move. That way they don't have to create separate schedules just to move loks around and tie up the track (I think that's called Lz for 'Lokzug'). I don't think these loks have provisions for sharing catenary power." Below is a link to a video of a multiple Lz:

Click here to see a video of a Lokzug.
Click here to see a video of the destruction of a pantograph.

(2) Some of the eloks have markings like H and V next to the driver's door. Is that abbreviation for front and rear in German?

(Answer - Tom Orle)

Used to be until the 50's. It has been replaced by '1' and '2'. 'V' stands for 'Vorne' (front) and 'H' stands for 'Hinten' or rear. Btw - in those days the locos used both panto's up. If you look carefully at older pictures, you'll notice that the old panto's only had one slider making contact with the catenary wire. Any loco using that kind of panto always ran with both up. Newer panto's have 2 sliders and therefore can get away with using only one panto up.

(3) Which way should the single arm pantograph run? With the elbow joint facing front or rear?

(Answer - Tom Orle)

Either way - however they're designed. Some don't have the space on the roof for the elbow to go in one direction or other due to placement of the main circuit breaker, hydraulic panto raising cylinders or other stuff.

(4) The Swiss Ae 8/14 has three pantographs. Should the middle one be up normally?

(Answer - Jacques Vuye AKA Dr. Eisenbahn)

In fact it originally had four!

This because it is essentially two loks, permanently coupled sharing a large part of their main components with the Ae4/7 (motors, transmissions, compressors, etc).

It was running on two pantographs for most of its life and the same rules apply as Tom described in his [answers]. The third one, seen currently on the Museum lok in Erstfeld, is in fact a dummy and serve no practical purpose! The "functional" ones are those at the "rear" of each half lok.

(5) In prototypical operation, when the elok arrives at the station and has to switch directions, would the pantograph rise automatically, or does it need to be pushed up and down like the street car in Harvard Sq?

(Answer - Tom Orle & Marout Yasuo Sluijter-Borms)

They are raised by compressed air and the engineer has controls in the cabs.

Upon arrival at the station he lowers the rear panto and after he himself moved to the other end pushes the button to raise the other. Note also, that when a train is coupled or uncoupled by the worker standing between the loco and the first car - the panto is dropped. This is to prevent any possibility of electrical shock to the coupler if there were any defect or leakage in the loco's electrical system. You can see this at dead-end stations like Munich, Stuttgart and Frankfurt all the time.

THis is a safety precaution, necessary when the train needs electrical power:

On the buffer plate there is a large single-pole connector with big insulation.

It carries between 1500V in NL (full catenary load) or 3000V in other UIC compliant locos.

It is locked into a holder on the buffer plate and the lock uses the same key as the main circuit switch on the loco.

The key can only be removed from the main control panel if:
-the loco is totally dead (all systems set to OFF)
-Catenary circuit breaker is in the OFF position
-Both pantos are lowered
-Main circuit control is set 0

That way, it is certain, the connector has potential 0 V and can safely be hooked to or unhooked from the carriages.

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