Thursday, October 8, 2009

Hotbox Detectors

When the distance between railway employees started to exceed the distance an axle takes to turn into a hotbox, it was time for Canada's railways to introduce some new technology. Longer and heavier trains, more and varied dangerous commodites, and greater concern for the economic, environmental and safety risks to neighbouring communities also contributed to the implementation of wayside hotbox detectors.

The development of wayside detectors meant that train crews bore even greater responsibility for the safe movement of their own trains. CP's detectors (MacGregor, Manitoba, top and Shannonville, Ontario, above) had wayside monitoring equipment connected to a large digital display board. The board displayed the location of the hotbox or other defect such as dragging equipment or sticking brakes, based on the train's axle count, counting forward from the tail-end of the train.
Tail-end crews read the display from the van or Park car, and if there was a defect, the type and side would be indicated by five lights mounted above and below the board. Top-left: defect on left side of train. Top-middle: multiple defects. Top-right: defect on right side of train. Bottom-left: dragging equipment. Bottom-middle: system operational, detector operating. The display readout was 11 inches deep, 30 inches high and 48 inches wide. Views of CP installations from aboard VIA's Canadian, Nipigon Sub (above) and Griswold, Manitoba:

By 1983, CP had installed 67 detectors in Ontario alone. Double-track segments of CP's network necessitated the placement of two detectors per site. On CP's double-track east of Winnipeg, Manitoba, here's a double-track detector installation at Mi 83.3 Keewatin Sub, near Molson:

CN's detectors didn't have display boards. In October 2001, crews installed a detector at Mi 179.6 Kingston Sub. A backhoe dug a hole, then there was shovelwork to be done. Even with all this technology, somebody still has to get down in the hole and dig:

The detector location is chosen based on track profile (relatively flat, not requiring braking near the installation), regular spacing across a subdivision, road access for the signal maintainer, and proximity to cities. Crews don't use the radio in the vicinity of the scanner, as they listen for the message : "CN detector Kingston [Sub] North [track] temperature [# degrees] C, speed [in mph], detector out." The message is transmitted by a short aerial placed atop the signal cabinet, and is only audible near the detector.
A simple "HBD<-- a="" are="" beside="" detector.="" detector="" div="" dragging="" equipment="" hotbox="" impactors="" located="" nearby="" new="" on="" parallel="" points="" pole="" rail:="" spray-painted="" telegraph="" the="" ties="" to="" way="" with="">
Nearby installations are at Mi 190 to the west and Mi 163 to the east(below).

Detector information is also transmitted to a remote detector operator (RTCMech in Edmonton) who communicates with the rail traffic controller, who in turn communicates with the train crew. When the detector at Mi 179 was installed and tested, the entire menu of message programming choices was given, including every CN subdivision, numbers etc.

Brian Schuff shared a photo of a CP detector, with a freight train led by 3127 about to pass:

Running extra...
The November 10, 1979 CP Rail derailment in Mississauga led to widespread hotbox detector installation. Hazel McCallion was mayor of Mississauga then, as she still is. Born in 1921, she doesn't actually have to campaign much anymore to be elected.
Just finished listening to Words that Work by Frank Luntz. He introduces 21 words and phrases for the 21st century, suggesting "peace-of-mind" insteady of "security", government "investment" instead of "spending", but in an obvious oversight, didn't mention "quick and dirty" at all. Polls and pols, such as Tom DeLay and Newt Gingrich receive lots of attention, belying Frank's work environment.


Train Geek said...

I had no idea they had digital displays on them. I suppose those had to go before the cabooses disappeared.

VIA 1 had to stop around mile 10 of the Rivers sub yesterday because the hotbox did not transmit. They had to manually check the train before proceeding... surely a pain in the butt for the train crew and for the (already late) passengers.

Oil-Electric said...

Very interesting story! The "axle count" reminds me of the crew on board Nickel Plate Berkshire 765 relating how she always tripped the HBT, which they figured out was because of the axle count. Being a 4-6-2, the pony passed, but the large diameter drivers scrambled the system! Still, they were obliged to "make sure" at their next stop. GIGO.

Eric said...

Thanks for those stories Steve and Robert. Better safe than sorry in both cases. Hate to have anything happen to 765 - a good-looking locomotive.

Manny said...

Wow Eric, what a great writeup about a seemingly forgotten aspect of the 80s. I had no idea there were so many of those detectors. The late Bill Coo mentioned the one on the Keewatin sub in one of his books but I think the mileage was a little off. Either that, or there was another one along that stretch of track. I think he mentioned one around mile 92 or 94?

Interesting to note too your train (#2?) was on the left-hand running segment between the magnificent flyover at mile 91 (removed in 1984) and the lakehead.

I sure am glad you were documenting all this stuff back then, at a time when film and developing were expensive.

Eric said...

Thanks Manny, yes film/developing was expensive and if I'd had a digital camera I would have many, many more images of those detectors and other trains.

Bill Coo mentions "Mi 94.5 on the bank by south track a 10-foot tall HBD". I think his mileages may have been off, because a 1994 CP Rail employee timetable mentions detectors on both tracks at Mi 65.7 Whitemouth, Mi 83.3 Molson, and Mi 109.2 Oakbank. My original notes mention Molson.

Here's another mystery. On the westward trip, I noted and sketched "interesting installations every 2-3 miles near Molson, like HBD's but with no screen, with one at Mi 83 with a screen." Wonder what those were?

Anonymous said...

Hi I just stumbled on this blog and worked as a summer intern for the company that made the equipment referenced here. It was called Oregon technical products and my dad was a long time employee there. I spent the summer of 1982(?) puonding in the lexan lenses that made up the three digital numbers. Had a lot oif hurt fingers that summer! the whole gorup of guys at OTP were a great bunch and wonderful memories there.

Eric said...

A., great to hear from you. Well, somebody had to put those things together. The system certainly was unique in appearance, plus very 'high-tech' for its time. We take so much of our technology for granted now, but this was very much cutting edge.

Interesting to hear from someone who was there!

Thanks for your comments,

Anonymous said...

Hi it's me your annoymous summer intern again. My name is Dave and I stumbled back on this page once again and thought:

a) I'd apologogize for all of the mis-spellings in my earlier post

b) add a little more color. That summer I built around 900 of the lighted "triple-8" signs. Each one had a row of 8's on the front and back and there were about 21 separate lexan lights that went into each 8. They were installed by holding them between your thumb and forefinger and then smacking them hard with a rubber mallet driving them in. The secret was to let go just before the mallet struck home and to prevent your fingers from getting hit.

The steel plates mounted between the tracks for dragging chains, etc. were made of 1/2"(?) steel plate formed with a a series of 45 deg beneds so that they created a "teepee" between the tracks. Mounted under the plates were microphones embedded using silicone gel inside cast aluminum duplex electrical boxes. The chain would hit the plate, make a loud boom and the microphone would record the hit. I tested those things with a 10 LB sledge hammer.
Hope this sheds more light on these really cool detectors. My dad was the manufacturing engineer for OTP, the company that made them. All designed and built in Belmont, CA.


Anonymous said...

correction not 900, 90

Eric said...

Hi Dave,

Great to hear from you again. There is still a lot of interest in these unique installations. So, it's great to hear from someone 'who was there' at the time.

Don't worry about spelling mistakes. Here at Trackside Treasure, ever post is run through the shoulder-mounted spellchecker. It is supposed to catch all the miss steaks.