heated switches

[dh28473]

Who controls the heat for the switches on the trackes? Is there a thermostate or the railway goes by the weather and shuts them off? I'm looking at cn.thanks 28473

 

[BaltACD]

dh28473

Who controls the heat for the switches on the trackes? Is there a thermostate or the railway goes by the weather and shuts them off? I'm looking at cn.thanks 28473

Any way that you can think of!

In some cases they may be thermostatically controlled along with a precipitation montior to detect rain or snow.

In other cases they may be controlled by the Train Dispatcher.

In other cases MofW personnel must ignite the propane fueled heaters, in some places this done by signal maintainers.

In still other cases 'smudge pots' (kerosene fueled, open flame heaters) are lit by MofW personnel.

Heat is only required when percipitation occurs with below freezing temperatures to prevent switches from becoming ice locked or snow locked.  Cold weather in the absence of moisture is no problem.

Carriers decide where switch heaters will be placed based on normal weather patterns and the priority of the rail line involved.  In general, there are very few switch heaters East of the Mississippi and South of a E-W line through Richmond, VA.  West of the Mississippi I don't have any knowledge.

[mudchicken]

"In some cases they may be thermostatically controlled along with a precipitation montior to detect rain or snow." .....often referred to as a "Snorkel" device, looks like a larger version of a bunsen burner in a chemistry lab with a little mesh screen on top.

In urban areas, natural gas from the local utility is used instead of a propane tank. (some signal maintainers hate them because of local delivery pressure issues that don't normally come with propane tanks until they are almost empty)

The "dragons" use can be supplemented with little electric motor bellows blowers to get more flame for less buck along with the ability to blow flakes and ice crystals out of the points and moving parts before they land and stick.

As BALT points out, there is an art to placing the heaters  and when to use them. RTD Denver's transit people with light rail are still learning the hard way. It's too soon in this light winter to see if they got the message on their two functioning commuter lines.

Not as common as it used to be, but you still hear the DS quizzing the trains in a given area what the weather is doing so he/she can gauge when to flip the switch.

(With the advent of the hydraulic switches placed out in the middle of nowhere on dark territory, those conversations are slowly coming back into common use....and also when the red vegetable grease starts burning where they formerly used graphite )

[jeffhergert]

I've often heard dispatchers asking trains about weather conditions.  They will also ask sometimes which heater(s) aren't working.  They get an indication of heaters that are working or malfunctioning as a whole at a control point.  It doesn't necessarily tell them which one(s) aren't working.

Some of the newest control points have some kind of electric radiant heat type of heater.  I've been told, by none experts, that it's under the rail.  It also doesn't seem to work as well as the forced air heaters.  Someone, another none expert, said they work fairly well if the are turned on before they are needed.  That if they wait too long they can't catch up with any built up snow/ice.  I've noticed that a couple of these CPs now have propane tanks and actual switch heaters installed.

Jeff

[BaltACD]

One recurring problem with propane fueled switch heaters is that the piping from the fuel storage tank to the switch heaters themselves is subject to the effects of recurrent vibrations from passing trains and thereby become suseptable to breaking.  If the break happens when the heater isn't in use, it can be out of fuel when it is needed.  If the break happens while the heaters are in use it is likely that the gas will be on fire at the location of the break.

The Perfect switch heater has yet to be developed.

[Paul_D_North_Jr]

mudchicken

. . . In urban areas, natural gas from the local utility is used instead of a propane tank. (some signal maintainers hate them because of local delivery pressure issues that don't normally come with propane tanks until they are almost empty) . . . 

I've been told that pressure issue is more prone to happen when natural gas demand is high - as it is during colder weather (sometimes condensation will freeze in the gas line, too), when the switch heaters may be needed the most . . . 

- PDN.