Asymmetric Tri-Lights

 When one thinks of the North American tri-light signal configuration (circular target with the lamps clustered in a triangle) one might assume that if the lamps are not set in a single large housing they would consist of single lamp modules kit bashed into a triangle instead of a vertical stack. For the most popular color light signal modules, the Safetran CLS-20, this is the case, however over the years the industry has produced some modular tri-light designs that don't use a common lamp module.

Of course I was prompted to write this post after being confronted by a tri-light product from our old friends at L&W. Purchased by Amtrak for its New Haven to Boston "Shore Line", this tri light has a single lamp module at the bottom with a double lamp cast aluminum housing above. From the front it looks like three singles due to the characteristic gap in the middle, but closer inspection reveals the true configuration.

 

 

The second example is from Transcontrol, a company typically associated with active grade crossing equipment. Somehow they were part of the contract to re-signal Hoboken Terminal around 1984 and their tri-light solution involves two standard lamp modules above an extra large one, which I assume serves as a junction box for the whole assembly. (Note, until this post I was unaware that Transcontrol made signal hardware and I might follow up with them in the future if more information presents itself.) 

One might consider the crop of asymmetric tri-lights to be offshoots of the original US&S style "TR", which features a single cast iron housing with three individual lamp sockets. Signals need terminal blocks to connect the interior wiring to the external wiring and terminal blocks take up space.

If you're wondering how the CLS-20 does it, there are openings on top at the 11 and 1 o'clock positions that match with other openings at the 7 and 4 o'clock positions. For a tri-light configuration the lamp modules are mounted 4 to 11 and 7 to 1. A supplier who can handle both vertical and tri-lights with a single SKU is naturally at an advantage so as a result the asymmetric tri-light has faded into history.

CSX Removing Cab Signals Is Not an "Upgrade"

Ever since CSX turned against the cab signaling system on the RF&P, the "Rule 562" cab signaling without fixed wayside signals on the former Conrail Boston Line has looked increasingly out of place. The only part of Conrail's 1990's cab signal push that was taken over by CSX, the Boston Line east of CP-187 has technically required CSX to entire that the 4 or so daily road freights have CSS equipped leading locomotives that have also carried out the perfunctory cab signal test. Although Selkirk yard has to handle similar requirements for freight on Amtrak's Hudson Line, those can be handled by a dedicated pool of local power. Road freights, on the other hand, are likely to arrive with unequipped leaders requiring a potentually time consuming engine swap.

Although Boston Line cab signals were recently extended east of Framingham as part of the MBTA's ACSES PTC implementation, CSX has become increasingly vocal about removing the Conrail era system west of Worcester. This "demand" has made it into a state funded East-West rail corridor improvement program and if you think that using state funds to adjust a fully modern, privately owned signaling system is insulting, the state has the audacity to label the cab signal removal as a "capacity improvement".

For anyone not familiar with the technology, continuous cab signals provide real time block status updates when a train is within the typically 2-mile long fixed track circuit blocks. Through this mechanism cab signaling is what provides a capacity improvement over fixed wayside signaling. (Recall that as far as I am aware, ETMS PTC systems are not cab signaling as they currently do not meet the requirements for safety critical operation. IE they can be trusted to stop trains, but cannot make them go.)

So why is a state government website proclaiming this to be a capacity improvement? It's possible that they figure its best to frame every state funded change as an improvement and assume that only me and three other people will ever notice. However a recent photo I came across hints at what CSX might be doing to make this statement true. 

The photo shows a Conrail era signal in the Pittsfield area displaying a Rule 280a "Clear to Next Interlocking" 'C' lamp. This is supplied in Rule 562 territory to allow trains to proceed to the next interlocking at track speed in case of cab signal failure. Sometimes called "super clear" it is normally a hard signal to catch in the wild since cab signal failures aren't typically predictable. While it is certainly possible the photographer got lucky or caught wind of a special movement, I believe a more likely situation is that CSX is running non-cab signal equipped leading locomotives on its through freights and relying on Rule 280a as a standard operating procedure. This would create functional blocks over 10 miles long, thus seriously reducing capacity. So in theory, by jamming a broom handle in the spokes of the bike it is riding, CSX could have created the conditions where removing continuous cab signals would increase capacity. 🙄

GRS and the Age of Aluminum Signals

People talk a lot about disruption and an often overlooked disruption was the North American railroad signal industry's transition from cast iron to aluminum in the 1980's. Here I am talking about the railroad signals themselves, not the entire signaling product line, but the ability for new companies to enter the market selling  new types of bulbs in a housing put a lot of pressure on the US&S / GRS duopoly. Both companies tried to respond to the new competition, but only one was successful over the long term. 

Iron melts at around 2300o F while aluminum melts at around 1200o. The former requires a foundry and expensive sand molds, the latter can be done with an electric furnace and can get away with using permanent molds made of steel. By 1980 cast iron had been the material of choice for railway signals going back almost a century with GRS and US&S operating the necessary "smokestack" industrial infrastructure to make the components at scale. However, since World War 2 aluminum had become much more common in everyday products like cars and bicycles, and investors looked at the high margin railroad signaling duopoly and wondered if their might be a better way. 

Safetran CLS-10

Safetran was the best known starting with the aluminum CLS-10 that directly competed with the cast iron GRS D Type modular color light signal. The aluminum (and solid state) Unilens was developed to go after the searchlight market and the NR went after GRS's famed G Type. About the same time both L&W and Harmon also entered the market with their own cast aluminum signal modules. The moat had been bridged and aluminum would eventually force cast iron signals out of the market entirely.

Of course both GRS and US&S were going to complete in the new aluminum signal market with US&S seeing some modest success with its clean cut modular box and CR-2 twilight. GRS on the other hand did not do so well.  In 1989 GRS was purchased by the Sasib Railway Group of Italy and they came out with a product family of aluminum signals. The better known family member was a 3-lamp monolithic signal similar to a US&S style P or R. This had some high profile sales such as the LA Union Station and Dallas Terminal re-signaling projects.

After Sasib was acquired by Alstom in 1998 this type of signal was still being sold, just with the Sasib logo scratched off.

The second offering in this family is the much rarer tri-light type intended as a G-Head replacement.  The only place I have noticed them was on the MBTA Dorchester Branch at Readville. Again, note the Sasib logo.

What I have yet to find is an aluminum D Type replacement to compete in the most popular part of the signal market, modular single lamp color lights. Of course maybe that's the point. GRS saw the market was saturated with lower cost competitors and decided not to bother. US&S did try to compete and was rewarded with lackluster sales. So why did the other two signal types fail? 1990 was a bit of an odd time in the railroad signals market. Traditional searchlights were still selling and it still made economic sense for railroads to refurbish old signals and reuse them in new signal projects. Used signals were in abundance as main line track was trimmed down from what they had been in the 1960's. It would be the better part of a decade before Safetran CLS-20 sales exploded as part of the Darth Vader boom of the 2000's.

Generic Canadian Pacific 3-stack.

In hindsight the bare bones GRS 3-lamp monolith may have simply been ahead of its time as Canadian Pacific has more recently adopted a similar no frills box as its standard new signal.