>>131928 [OP]
Not exactly. The discone is for shunting VHF radio communication and the wire is for mainline MF or VHF radio communication, signal for the second is usually provided by contact wires or SCI feed wires used as waveguides. But as I can see they started to refuse from the discones, dunno why exactly. Managed to take both signals in sufficient quality from the wire maybe? Not quite good at this.

I think the 2ES6 on your pic still has a separate antenna for the yard radio, namely that cone-on-a-cube thingy to the left on the cab roof.

Just out of curiosity, do they use satellites to determine location? I wonder if one of those white antenna housings protects an antenna for a GLONASS receiver.

Otherwise, if I were to hazard a guess by scaling the antenna size i'd say it's in the UHF band... maybe as high as 33cm in wavelength?

These Russian trains are fascinating. :-)

>>131953
I have already spoken of this in RZD thread.

> However, our modern signalling (KLUB-U/BLOK) maybe is based on block sections but still is fairly advanced: it can monitor up to 5 block sections ahead, the position of the locomotive is tracked using GLONASS (previously GPS) with a precision of a few meters, which allows some useful resulting features like targeting system which helps a passenger train to stop at platform more precise and effective when working in advice mode or to do it automatically if automatic driving is equipped and on, it can maintain train speed within limits and stuff like that. Almost every line with sufficient passenger train traffic is equipped with this signalling, but, as a rule, all rolling stock on such lines has appropriate onboard systems, however, ALSN/ALSM and KLUB-U/BLOK equipment is mutually compatible, but in this case only supported by the inferior system features will work.

Every KLUB-U/BLOK computer uses interactive map which contains all important points of the line including signals, platforms, speed restrictions, warnings and other stuff you need to provide to the driver or even to drive the train automatically, BLOK is able to contain also the entire track profile of the line.

>>131953
And about the antenna cap, I think the answer is on the picture above, it is probably for the denoted digital communication antenna. However GLONASS receiver is this white box on the top of the picture so maybe an antenna for it is hiding inside this little cap against the big one. Never have seen the "map" of all roof equipment of an electric locomotive, unfortunately.

Trust me to forget all abnout GLONASS's existence... (feeling very grumpy at self) After all, my smartphone has a dual-system (GPS/GLONASS) locator.