Where you will find ABS signals
I’ve mentioned “ABS territory” in the last few posts – most of the alignment is in that category. In ABS territory, trains have a dedicated right of way and intersections are protected by crossing gates.
You’ll see signs on the alignment saying “BEGIN AUTOBLOCK” which designate entering ABS territory from pre-empt territory, and “END AUTOBLOCK” which designate leaving ABS territory and entering pre-empt territory. One example –
which extends through…
ABS territory includes:
Note: the above map isn’t perfect – there are some platforms on the border of ABS territory that have pre-empt signals in one direction & ABS in the other – and then a platform such as Lloyd Center isn’t in ABS territory, but leaving Lloyd Center eastbound there is both a pre-empt and an ABS signal – Goose Hollow is also similar, except there is both an ABS and a pre-empt going westbound. But the map should give you an idea at least. From west to east:
Westside Blue Line – 12th & Washington westbound through the tunnel is ABS territory. Goose Hollow westbound also is ABS.
On the Yellow Line -the Vanport Bridge after Kenton/Denver and points north
Red, Green, and Blue – from points east of Lloyd Center through the airport (Red), Clackamas Town Center (Green), and Gateway (Blue)
And for the Blue Line – Ruby Junction and points east.
All ABS signals and combination signals (more on that in a later entry in this series!) are numbered to make them easy to identify and for operators to use when reporting their location to Rail Control.
On the Blue, Red, and Yellow lines, signal numbers correspond to their distance from the 11th Ave terminus downtown.
And point of trivia (not like this whole blog isn’t trivia, but whatever) – most eastbound main signal numbers end in 4, most westbound main signals end in 6.
Blue Line – east side
The signals east of the 11th Ave terminus on the Blue Line alignment have no designating letter, but the signal numbers increase as you head east from 11th Ave, and the numbers give you an estimate of their mileage from the 11th Ave terminus up to Signal 160, which is used by trains leaving the tail track into the Cleveland Avenue platform.
Blue Line – west side
The numbers of signals west of 11th Ave terminus all begin with W and go up to W1778, which is one of the signals to leave Hatfield Government Center, nearly 18 miles from 11th Avenue.
Signals along the Yellow Line alignment from Interstate Rose Quarter through Expo Center begin with N2A and N2B, and go up to N62 at the Expo Center, a little over 6 miles from the 11th Ave terminus (I know these maps aren’t perfect, they’re just to give an idea of location and distance).
Signal numbers on the Red and Green Lines correspond to their distance from Gateway
On the Red Line airport alignment, the signals begin with A – the lowest number is A88 (which is visible to trains heading into Gateway) and they go up to A552 which is one of the two platforms at the PDX Airport Terminus. These numbers don’t relate to the distance from 11th Ave terminus – they correspond to the distance from Gateway, which is about 5 and a half miles away.
Signals along the Green Line alignment to Clackamas Town Center begin with C. These go from signal C14 near Gateway where the Green Line diverges south up through signal C630 which is the tail track signal at Clackamas. Again, like with the Red Line Airport extension, these numbers correspond to the distance from Gateway rather than the distance to 11th Ave.
The ABS and combination signals on the downtown mall begin with M, beginning with the M176 signals in the Jackson turnaround and going up to the ABS & combination signals near Union Station and on the Steel Bridge (M16 is the lowest signal number at the Steel Bridge).
That pretty much covers ABS signals I think… up next, pre-empts!