Cab signals?

I understand Framingham-Worcester uses cab signals from Worcester to Framingham, and the Northeast Corridor uses ACSES, but what is the complete 'inventory' of cab signal required lines throughout MBTA CR? And except for cab signals vs. ACSES, are all cab signal systems the same and interchangeable? Or are there different flavors of cab signals?

TIA. Dave

*updated 3/26/15. For lots of detail, see posts below.

PLACEHOLDER post. As we collect info, I'll keep a running current list right here. So far I think I know:

South:
Framingham-Worcester: From Worcester to Framingham = cab signals, waysides only at interlockings. From Framingham to COVE: Wayside only, ABS

Needham: from South Station to near Forest Hills, shared track with NEC (see NEC below). Forest Hills to Needham Hts: Wayside only (CTC)

Franklin: from South Station to near Readville, shared track with NEC (see NEC below). Readville to Forge Park: Wayside only (CTC)

Northeast Corridor (NEC): ACSES plus waysides

Stoughton: No wayside (except at interlockings), cab signals

Fairmount: No wayside (except at interlockings), cab signals

Old Colony: No wayside (except at interlockings), cab signals

Greenbush: No wayside, cab signals only


North: no cabs, but signal system details:

Newburyport: North Station to North Beverly: no cabs, CTC or ABS (?). North Beverly to Newburyport: no cabs, wayside CTC (modern)

Rockport: Beverly Junction to Rockport: no cabs, unidirectional wayside ABS (ancient)

Haverhill: North Station to Oak Grove: no cabs, wayside CTC (modern). Oak Grove to Reading: no cabs, unidirectional wayside ABS (ancient). Reading to Wilmington Jct: no cabs, waysides CTC (modern). Wilmington Jct to Haverhill: no cabs, wayside CTC (varying ages)

Lowell: BET to Wilmington: no cabs, wayside CTC (ancient). Wilmington to North Chelmsford: no cabs, wayside CTC (modern)

Fitchburg: no cabs, waysides (CTC)

On Amtrak's NEC,Cab signals with ACSES.

dbperry wrote:PLACEHOLDER post. As we collect info, I'll keep a running current list right here. So far I think I know:

South:
Framingham-Worcester: From Worcester to Framingham = cab signals, waysides only at interlockings. From Framingham to COVE: Wayside only, ABS
Needham:
Franklin:
Northeast Corridor: ACSES plus waysides
Fairmount:
Old Colony: No wayside, cab signals only
Greenbush: No wayside, cab signals only


North:
Newburyport:
Haverhill:
Lowell:
Fitchburg:

-- Needham: cab signals end right after NEC split at the controlled passing siding that starts next to the Orange Line storage yard at Forest Hills. Wayside-only CTC to Needham Heights--generic tri-color signal heads. T was still doing fresh installations of that in 1986 when the line was rebuilt. Last signal head is a little past the Hunnewell St. overpass.

-- Franklin: Likewise cabbed only at the NEC split. Ends at the interlocking at Readville that starts the double track. CTC w/waysides...very old NYNH&H installation to Franklin Jct., 1988-installation T job for the Forge Park extension. Mostly the same generic tri-color heads as elsewhere. The age of the installation is why for the Foxboro extension study the Framingham Secondary was going to be cab signaled all the way between Walpole and Mansfield despite regular revenue service ending at Foxboro. The fiber plant for the signals is cheaper to tie into the NEC end than the Franklin end.

-- Worcester: Back Bay to Framingham Jct. 1960's-installation ABS w/searchlight-style waysides...the absolute cheapest, most limited thing Boston & Albany could get away with at the time. This is why wholesale rip-out/replace is necessary. It can't even be easily modified for new crossovers in its current state.

-- Stoughton: cabs were installed same time the NEC's were in the Canton vicinity (1960's?). Last signal head is at the Route 27 grade crossing a block north of the station. No waysides except for interlockings, unlike the NEC (that's Amtrak's exclusive preference).

-- NEC: has been cabs through most of MA longer than it has anywhere else on the Shoreline. Everything rebuilt 15 years ago for electrification.

-- Worcester Line, Framingham-Albany: mid-1980's fresh Conrail installation when they rebuilt the line. Conrail did searchlight-style heads and not tri-color like the rest of the T's non-Worcester southside heads, which is why they're different out there.

-- Old Colony and Fairmount obviously more recent installs. Cabs, no intermediate waysides, generic tri-color signal heads at interlockings.


Middleboro Secondary and Cape Cod mainline to Hyannis have a derelict 1982-85 installation wayside installation with unusual vertical traffic light-style waysides unlike anything else on the system. It made it as far as the testing stage, but never worked right because the crap jointed rail did such a lousy job transmitting track circuits. It was abandoned before it ever went into revenue service when the Cape Codder got the axe. Nearly all of the signal heads are still there turned away from the ROW, but other than the trenched cable conduits (which will be handy if/when Middleboro-Bourne extension happens and save them a pricey EIS) it's all got to be replaced. Active CTC dwarf signals protecting both sides of the Canal Lift Bridge, and active vertical traffic light-style heads protecting Cape Jct. on both the mainline and Falmouth Branch sides.



Northside:
-- Modern CTC w/waysides on Fitchburg (new installation). Not sure how many ex-B&M searchlights remain west of the current construction area...all of the new ones are generic tri-color.
-- Modern CTC w/waysides, Western Route Plaistow-Brunswick (2001 & 2009 Downeaster installation). Think there still are some searchlight heads cut over from old to new systems.
-- Modern CTC w/waysides North Beverly-Newburyport at the end of the double track (1997-98 installation). Generic tri-color heads.
-- Modern CTC w/waysides , Western Route to Oak Grove on the single track (1975 Orange Line-related installation). Generic tri-color heads.
-- Modern CTC w/waysides Reading-Wilmington Jct. on the single track (1979 installation), and on the Wildcat Branch. Generic tri-color heads.
-- Modern CTC w/waysides Wilmington-North Chelmsford (maybe Nashua?) on the Lowell Line (early-80's T rebuild). Not sure if any ex-B&M searchlight heads remain out here or if they all went tri-color.
-- Ancient, unidirectional ABS, Western Route from the start of double track at Oak Grove to end of DT at Reading.
-- Ancient, unidirectional ABS on the entire Rockport Branch. Rockport + Reading are the two most archaic signal installations left on the system now that Fitchburg's been completely renewed.
-- ABS on Lowell Line BET-Wilmington. This wasn't modernized in the 80's like the outer part of the line was, which is why you see more signal-related delays on the inner half of the line. Really needs replacement, and it's got that funky asynchronous speed limit of 70 MPH one direction, 60 MPH the other direction.
-- Old (CTC?), Eastern Route main to North Beverly. I don't think it's ABS...but it definitely is old. Tri-color heads...don't think there's any searchlights here.
-- CTC, Western Route Wilmington Jct.-Plaistow. Of varying ages...some segments (Lawrence-Plaistow?) nearing replacement age and are unfunded mandates in the capital budget.

dbperry wrote: are all cab signal systems the same and interchangeable?

No. There are several different systems out there, and locomotives expected to operate in the lead position on routes with different cab signal systems need to be equipped for all the systems used on those lines. I'm not sure how much duplication of hardware is required for multi-system compatibility, or if it can be accomplished with software updates.

MBTA3247 wrote:

dbperry wrote: are all cab signal systems the same and interchangeable?

No. There are several different systems out there, and locomotives expected to operate in the lead position on routes with different cab signal systems need to be equipped for all the systems used on those lines. I'm not sure how much duplication of hardware is required for multi-system compatibility, or if it can be accomplished with software updates.

Except for LIRR which has an extra signal aspect all of the stuff on the southside is the same bread-and-butter PRR pulse code cab signaling that's been around since 1922. The NYNH&H + Pennsy + NY Central overlap at Grand Central and Penn is what bound them by necessity to system interoperability. That's why CSX and NS can get around the whole East Coast without having to have a different cab unit on every line they go on. Elsewhere in the country...yeah, even when they're based on PRR cabs there's incompatibilities and too much fragmentation to contend with. East Coast has a BIG advantage over everywhere else at having 93 years worth of interoperable mass deployments.


PTC's gonna nicely blow that interoperability to shards, though. ACSES on the passenger lines, which isn't programmed at all for freight stopping distance. Then I-ETMS on CSX's and NS's lines. Including the ones that are cab signaled. And both ACSES and I-ETMS where significant freight overlaps significant passenger traffic and that freight stopping distance thing has to get squared, which is gonna be really interesting to debug and ought to cause at least a few all-new grudge matches between the Class I's and their passenger counterparts. And since the cabs are still there underneath working in tandem...same requirements as before. Except here on the northside, where thanks to Pan Am's cab signal prohibition the T has to be the guinea pig that designs, tests, and deploys the cabless version of ACSES that absolutely no one else is using. And if we know our T, we surely know how up-to-the-challenge they are at successfully deploying never-tested things on-time, on-budget, and without passenger suffering!

MBTA3247 wrote:

dbperry wrote: are all cab signal systems the same and interchangeable?

No. There are several different systems out there, and locomotives expected to operate in the lead position on routes with different cab signal systems need to be equipped for all the systems used on those lines. I'm not sure how much duplication of hardware is required for multi-system compatibility, or if it can be accomplished with software updates.

So for MBTA routes, do they only use one system of cab signals (other than ACSES on NEC)?

Yes, the MBTA has the same cab signal system everywhere they use one, which is the norm for all railroads. Though I wouldn't be surprised if some of the Class I's have multiple cab systems spread over their networks on account of all the mergers over the last few decades.

dbperry wrote:

MBTA3247 wrote:

dbperry wrote: are all cab signal systems the same and interchangeable?

No. There are several different systems out there, and locomotives expected to operate in the lead position on routes with different cab signal systems need to be equipped for all the systems used on those lines. I'm not sure how much duplication of hardware is required for multi-system compatibility, or if it can be accomplished with software updates.

So for MBTA routes, do they only use one system of cab signals (other than ACSES on NEC)?

Yes. 4-aspect, 100 Hz Pennsylvania Railroad pulse-code cab signals. And the NEC uses that too. ACSES is just the PTC overlay on top of the existing cabs. They work in-tandem with ACSES bootstapping on top of the cabs layer (confusing because some PTC systems--including the cab-less variant of ACSES that the T is forced to deploy on the northside because of the Pan Am cabs exemption--do more of the heavy lifting alone).

4-aspect/100 Hz/Pennsy cabs are the same universally-compatible system used on:
-- all of Metro North except the dark Waterbury Branch (planned but not yet unfunded)
-- all of NJT except the dark Princeton Dinky (exempt)
-- all of SEPTA except Cynwyd (planned), Thorndale (planned), and the last 2 stops on the West Trenton Line (bogged down in negotiations with CSX). Norristown Line cab signals are under construction and supposed to go live this Fall.
-- all Amtrak NEC, Springfield Line, Keystone Line/Harrisburg + Pennsylvanian/Pittsburgh (NS trackage) , Empire Connection + Hudson Line to Albany
-- all Amtrak D.C.-Richmond Regionals and VRE's Fredericksburg Line (CSX trackage). No cabs on the Lynchburger after it diverges, no cabs on Newport News and Norfolk after those branches diverge post-Richmond.
-- portions of Amtrak Capitol Limited (NS trackage)
-- portions of Amtrak Lake Shore Limited (CSX B&A mainline, Framingham to Schodack, NY + Amtrak Post Road Branch, Schodack to Albany-Renssalaer)
-- a few other Norfolk Southern and CSX freight lines emanating out of Virginia, Pennsylvania, Ohio (all ex-Pennsy or Conrail installations.)


LIRR's system is a 6-aspect version of the 100 Hz PRR system. I *think* (but don't quote me on that) LIRR trains are backward-compatible with the 4-aspect system because it's otherwise the same system except for the +2 extra speed codes, but 4-aspect trains aren't forward-compatible on LIRR without restrictions. The other systems (mostly emanating out of Chicago) either use different track circuit frequencies the 100 Hz onboard equipment can't read or have different rule enforcement quirks deviating from the East Coast standard that the PRR/100 Hz/4-aspect equipment can't interpret.

Fantastic info. Thanks for educating me.

What you mean Pan Am prohibition / exemption for cabs and PTC?

Whatever happened to PTC mandate / timeline? Wasn't that supposed to be this year? What is MBTA deadline for compliance and plan to implement?

dbperry wrote:Fantastic info. Thanks for educating me.

What you mean Pan Am prohibition / exemption for cabs and PTC?

Whatever happened to PTC mandate / timeline? Wasn't that supposed to be this year? What is MBTA deadline for compliance and plan to implement?

Pan Am does not use any cab signals except for the territory they access in Connecticut via the Springfield Line (which was a "new" freight rights addition to the B&M system swapped with Conrail in '82, after the line already had cabs installed). They only retain 4 or 5 locomotives on their entire system equipped with cabs. Because of all the legacy red tape on the northside lines the T inherited during the B&M bankruptcy PAR has a perpetual right of first refusual on any cab signal installations on its freight trackage rights. So the T can't t them anywhere except on the Newburyport and Rockport branches past Beverly Jct. where all freight rights have been 100% abandoned. PAR hasn't budged with that prohibition, including on the inner Fitchburg Line and Western Route south of Wilmington Jct. where there are no active freight customers and which they currently just retain as alternate routes. Thems the breaks for the T getting gifted so much nearly free territory from bankrupt B&M back in the day: cab signals shalt not extend to the northside.


Northside freight is expected (though unclear how) to obey ACSES in MBTA territory and be equipped. Probably with the T having to buy PAR the readouts for all their locomotives. But it still won't be cab signals. We're still talking separate things with that, which is why the northside's ACSES installation is going to be that totally unproven version that works without assistance from the cab signals. They (and the Downeaster) alone will be the guinea pigs who have to make that work...or hemorrhage money trying. Every other line in the country that is installing ACSES either does or will be running it on cab signals and the "known-knowns" learned from that setup after 15 years of active use on the NEC. Can't blame Pan Am for exercising a legally protected right of first refusal. Absolutely can blame the feds for leaving the T out in the abyss trying to figure this out by themselves.

There's been some rumbles that the congress critters will extend the PTC deadline to 2020.

The only other cab signal system is UP's CCS system used on the "Overland Route" transconn across Wy and Ut
Amtrak needs a UP leader when detouring on that route.

Backshophoss wrote:There's been some rumbles that the congress critters will extend the PTC deadline to 2020.

The only other cab signal system is UP's CCS system used on the "Overland Route" transconn across Wy and Ut
Amtrak needs a UP leader when detouring on that route.

The bill just--finally!, this week--passed out of Senate committee for a 12/31/2020 deadline extension and FRA arbitrator's discretion for 1-year extensions to 2021 and 2022 for any *specific* railroads who run into complications and need case-by-case basis help. But out of committee doesn't mean it'll get called up by the Majority Leader for a floor vote, and there is still the matter of passing it in the thrice-as-dysfunctional House. So there's at least par chance midnight 12/31/2015 hits with no vote taken whatsoever.

And forget about funding from the feds for fixing the mess the feds created...this is just the deadline extension. The $2B in railroad aid (cut back from $6B) that actually lets the MBTA's of the world have a faintest glimmer of hope of affording this is still in committee and may not make it out of committee at all before the 2016 election.

fascinating stuff. Another question: all things being equal, does having cab signals increase the allowable density on a given line? Or does it not matter, because the blocks are still the same size and dictated by the speed limits on the line?

dbperry wrote:fascinating stuff. Another question: all things being equal, does having cab signals increase the allowable density on a given line? Or does it not matter, because the blocks are still the same size and dictated by the speed limits on the line?

Doesn't really matter much since the blocks are the same, however it does help to speed things up. When a train passes a wayside signal showing anything less favorable than a clear signal, it must proceed according to that indication all the way to the next signal, even when the train in the block (or 2 ahead) clears that block. With cab signals, the train has a constant stream of code through the rails. The train will instantaneously know when the block or blocks ahead clear since the cab signal will upgrade right away no matter where in the block the train is so the engineer will not have to wait until the next wayside signal to increase speed. The only exception is having a restricting in the cab. You can't increase speed right away, since the rulebook requires you to not increase speed until the train has traveled 500 feet or 1 train length (whichever is greater) past the point where you received a more favorable cab signal indication. This is done mainly in case the cab signal flipped in error. (for all you know the rail ahead could be broken causing the cabs to drop out, but it momentarily makes contact with the other rail again causing it to go in and back out again) Restricting is the fail safe of the cab signal system since it relies on no code being in the rails, so the train must travel at the slowest speed, restricted speed.