Update on cleaning switches

 
Nokomis - Thursday, January 11, 2007 by: Jack Rusick

I am a little suspicious of your description of what is being accomplished in the article "Cleaning Switches" of December 24. The sign by the worker says "Derail", and although I know that some derails are in fact one point of a switch (which absolutely ensures the derail function), the absence of a switch stand to operate the point suggests that the derail may be one of the Hayes "manually operated - bend over and flip it clear" type. I will concede that it could be linked by a pipe connection to the switch on the "main line" but I doubt that is the case here. That arrangement is usually reserved for a busy siding, or one where there is a significant down grade between the siding and the main line. I suspect that neither case applies here.

Now - a little bit of an update on keeping switches clear of snow. I'm assuming that since you have spent the last few decades away from railway operations, there may be some changes that have occurred that not everyone is aware. I know that you are aware of the necessity for keeping the points of switches clear of snow, but I'm not sure if you've kept up with some of the more recent developments in this area.

Now, there are really two main ways of getting rid of the snow - melt it, or blow it away. Propane burners and electrical heaters (where ample power is available) are the main ways of melting it away. Snow melters are not very practical in extremely cold climates since the resultant water has to be drained away lest it freeze the points solid. As an aside, I have seen on installation where it was necessary to install an addional heater for the drain pipe since it would fill up with ice when the temperature got much below the freezing point.

The other method utilizes a hefty blower with air ducts running to the switch points. The blowers may be operated manually, by local or remote control, or they may be operated automatically by devices that sense a snow fall, and turn on the blower after some pre-determined amount of snow has fallen. I've seen detectors that use lasers that reflect into sensors when snow is falling and I've seen devices that melt the snow that falls into a collector to activate the blower.

The grand-daddy of all snow blowers was when the old New York Central mounted a surplus jet engine on a flat car and used it to clean the switches in a classification yard (circa mid-1960). The jet exhaust was facing forward and the car was moved throughout the yard by a switch engine. Unfortunately, the flying debris was not limited to snow.

The pictures with this story:

I took them in the summer of '05, at a CNR siding called "McGregor". This siding is located just west of the CN-CP diamond crossing at Nokomis where the CN main line (Melville-Saskatoon) crosses the CP Bulyea (North of Regina) -Nokomis-Lanigan-Watson-Melfort line. The siding is named after Vern McGregor who had a long and distingushed career in the CN Signal Department in Winnipeg. I took these (and several more) and gave him copies as a memento for him, since health problems did not allow him to visit "his" siding after it was built.

You'll see in the pictures that these snow blowers are quite a step up from the "leaf blower" types that the CP crew was using.

Now for the nitty-gritty:

Picture - "East 1069 Entering" (top of the page)- Looking west, approaching the east end of McGregor siding. The entering signal, power operated switch, and snowblower are in he foreground. A liitle further back are the "bungalow" (which house the control equipment), the main line leaving signal (high) and the siding leaving signal (dwarf signal).

Picture - "East Snowblower" (bottom of the page) - The blower motor, air intake (top) and ducting to the switch points. Also of note is the antenna tower just to the right of the bungalow. The supervisory communications (non-safety) are carried via radio these days. In my time a dedicated pair of wires was used for this function - and quite often the dispatchers telephone shared those wires.

Picture - "East Switch Point Detail" (right) - a close-up of the "buisness end" of the snow blower. The short tie in front of the vents protect them from being damaged by dragging equipment. The metal ducts direct the air stream into the switch points. I'm not positive, but, I think that the hose on the open point side is there to provide additional air to ensure that the main place where "harmful" snow could accumulate is kept clear of snow that could be compressed to block the switch point when the switch is moved from it's normal position.

The normally closed point doesn't need this because it would merely push the snow away during it's movement away from the rail. Yes, a similar "compressing" situation for the reverse point would exist if the switch were laying in the "reverse" position (switch lined for the siding) and then called "normal". Usually that condition only exists for the short length of time that the switch is lined in anticipation of a siding move. The switch's usual state is being lined for a "through" movement - i.e. a train on the main line.
 
 
 

 

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