NS Files to Replace Cab Signals with Back Door CBTC

It was no secret that Union Pacific was planning to dismantle Norfolk Southern's significant cab signal territory that was inherited from Conrail after it was absorbed in 1999. While 91% of NS locomotives are cab signal equipped, few if any UP locomotives are after they dropped their own cab signal system around 2022 and a cab signal requirement would hinder creating a nation-wide pool of yellow locomotives. Well it seems that NS has decided to go ahead and file for discontinuance of the legacy Conrail cab signal system notwithstanding the results of the merger decision and what is perhaps even more interesting/alarming is the proposed replacement. 

Unlike CSX or Union Pacific, NS had made significant investments in cab signal territory that lacks fixed wayside signals (what NORAC refers to as Rule 562). While both CSX and UP disposed of their former cab signal territory by just turning it off in favor of existing waysides, UP-NS would have to replacement the wayside capability on hundreds of miles of high density main lines. On CSX's sole Rule 562 route, the former Conrail Boston Line, the solution has been to run trains under Rule 280a "Clear to Next Interlocking" and petition the state for money to restore the wayside block signals. Something similar was my expectation since the UP-NS was announced with UP installing its flavor of wayside block signals from Perryville, MD to Cleveland, OH.

Well, it seems that NS's plan is to implement a PTC based Rule 562 with the PTC system transmitting track authority based on track conditions. While this is pretty much a statement on how ETMS PTC works, the sea change is that everywhere else PTC is still subordinate to good old fashioned wayside signal indications. This removes a sizable chunk of safety and security burden from the system under the concept of "PTC can make you stop, but it can't make you go."  NS's request to the FRA would take ETMS as a safety overlay change it into a bonafide communications based train control system, possibly without any additional modifications. 

Like with CSX, the NS plan would remove the cab signal codes as a source of movement authority which requires the installation of ETMS wayside interfaces at every track circuit block point and hand operated switch. Unlike CSX, wayside signals would only be present at control points with Rule 280a "Clear to Next Interlocking" being the available for various PTC failures. 

The roots of this plan might lay with a trial "Rule 562" system Union Pacific installed on the Hiawatha Sub in Kansas. Since UP discontinued its Automatic Cab Signal system in 2022, the Hiawatha Sub did not gain wayside signals, just PTC antennas at the old Signal Indication Points. Since nothing bad seemed to happen on this low density main line on the prairie, UP might be looking to bring the concept to populated areas regardless of how secure ETMS really is. This might even be the camel's nose for what PTC proponents had envisioned, nationwide moving block signaling.

It's not entirely clear if the FRA will bite, but public comments would certainly help make them aware of the stakes.  Coded track circuits are a secure and reliable way of transmitting movement authority that cannot be easily hacked by AI agents or whatever. Wide area ETMS outages are not uncommon because the system is effectively running on servers in some back office. Of course when these occur its mostly the passenger operations that get canceled because that's where the liability is.  The real shame is that even if the locomotives are no longer responsible for picking up the codes, they will likely exist in the rails transmitting block state for decades to come.

Amtrak Zephyr Trip Report: The More Things Stay The Same

The last time I rode Amtrak's California Zephyr route was in 2017 just after there had been massive re-signaling over the Donner Pass, Utah and the Moffat Tunnel route compared to my previous trip in 2014.  Well 9 years later and surprisingly not much has changed, including the remaining instances of vintage signaling still on the route. 

Starting off with what has changed, UP completed re-signaling efforts over the Donner Pass including the few remaining signals around NORDEN. The SP vintage interlockings around Truckee have also been replaced, However most of the old SP era signal gantries remain standing and along with some of the now turned ABS signal masts on the west slope. Elsewhere on the Capitol Corridor some SP target signals may have been replaced by vertical color lights, but most are still intact. 

The "what stayed the same" list is much longer. First off is DAVIS interlocking which is still equipped with searchlights and a trackside pole line. Relay logic and a US&S unit lever local control power are likely still in the old interlocking tower. Unfortunately I didn't get any photos so here's stuff from 2017. 

In Nevada the SP re-signaled territory west of Winnemucca has been largely unchanged. 

Likewise the classic DRG&W signaling has been largely left in place between Helper and Grand Junction due to the lack of through traffic and the resulting PTC exemption. A few interlockings and ABS signal locations have been replaced and most still featured "turned" replacements, however little replacement progress has been made since 2017. 

BOND interlocking at the junction of the Moffat and  XXXX subs has retained its DRG&W signaling despite being in the PTC zone.  

Also on the approach to Denver Union Station UTAH JCT and FOX JCT are both intact with their original DRGW relay logic and searchlight signals.  

Like everything with signaling, the situation can change without warning so if you are road tripping through any of these areas plan on some side trips to visit these locations.  

Amtrak Electrification Primer

While this blog is dedicated to railroad signaling, I occasionally veer into the command and control of railroad traction power systems because not only does electric power have to be switched and dispatched, but historically it has used much of the same technology used for both railroad telecommunications and railroad signaling. 

Anyway I was recently informed that some documentation regarding Amtrak's present day electric power operation has made it onto the Internet Archive and its definitely worth a read because the documents cover all three of its electrified "zones" (PRR, Hellgate and "Boston") and contain all sorts of easy to read diagrams and photos. It also covers details about the "100hz" signaling power supply including its generation and control which absolutely puts this in the railroad signaling wheelhouse.

How To Be an Amtrak Power Director (2021)

Amtrak Electric Operating Rules and Instructions (2026)