Norfolk Southern RR in Michigan; new towers popped up

I have been scanning a long time, but am a relative newb when it comes to railroad monitoring.

I have noticed since last summer that Norfolk Southern has several new antenna towers along their ROW in my area. They are about 17 miles apart, less than 100 feet tall, & they have UHF yagis at the top pointed along the ROW in each direction. What I'm curious about is; about 30 feet up on the tower, there are 2 long "outriggers", with some type of small antenna or sensor on them. These are mounted so that one is sticking out over the track, the other is sticking out away from the track (perpendicular to the ROW). I will try to find one that I can get close enough to get a decent picture of & post it here. Anybody know what these are?

Thanks in advance.

The towers are probably for Positive Train Control. The UHF Yagis are probably for the 220 MHz links between the tower sites and the trains. The other antennas you're seeing could be for GPS receivers or satellite data links.

https://www.fra.dot.gov/Page/P0152

https://www.aar.org/policy/positive-train-control

https://en.wikipedia.org/wiki/Positive_train_control

Thanks for the quick reply, W9BU. The links you posted were all very informative. I'll still try to get a picture of one of those towers to confirm that's what they are, but your explanation makes sense. The line they are on is in fact the route taken by Amtrak between Chicago and Detroit.

As an aside, the short stretch through Battle Creek referenced in one of the articles you posted is ROW that is owned by Canadian National; the two lines were consolidated several years ago onto one ROW to alleviate traffic congestion through downtown.

Thanks again!
P.S. Love the Joe Walsh quote!

This one is next to my house, are these what you are talking about?

That's them!
So the yagis are for communications to/from the train. I wonder why the others had to be so far away from the tower.

Its usually a little more complicated than that....and depends on the railroad and territory.

You have PTC coming online, as well as remote locomotive reporting, ATCS, status reporting and a few other things.

Out my way (which is all CTC with two mile signal spacing) each signal uses a folded dipole at each signal location for PTC on a short mast, the wayside boxes also support antennas for locomotive health reporting - and many have weather instruments reporting back on another datalink.

This is in addition to wireless/wireline codeline interfaces/ATCS and internal data links.

What you also see that's expanded is the GE Trip Optizmer and NYAB LEADER programs that are installed in many locomotives that needs downloads at different points of origin for train profile/data. These programs "Assist" the engineer with train handling and some version have a form of "auto pilot".

NS is has some funky installations while UP seems to have pretty standard ones.

I'll try to get another photo if I can.

I had a NS motor the other day, I counted 13(one-three) 1/4" heliax hardlines coming into the nose.

Tim

Ouch. I think what I have seen out west is about 7:

Voice radio (VHF)
DP A (UHF)
DP B (UHF)
EOT (UHF)
PTC A (220)
PTC B (220)
Event Recorder (900)

Basic PTC antenna count

The basic PTC install has these antennas:

GPS x2
Cell x2
WiFi x2
220 x2

Most locomotives already have:

VHF voice x1
UHF HOT/EOT x1

If Distributed power equip'd

UHF x2

There are a few other systems that may require more.....