July 2014 Union Strike

A tentative deal between the MTA and LIRR Unions to avert a July Strike has been reached. See this post for more information.

Saturday, February 8

Switch Heaters

There are few scenes more picturesque on the LIRR than that of looking over the edge of the platform at Jamaica on a cold, snowy morning and seeing the interlocking glowing with switch heaters.

When snow and ice tighten their grip on the region, the LIRR 'fires' up dozens of switch heaters all over the railroad to keep the ice and slush from preventing the switches flow throwing.  These switch heaters play a silent role in keeping the trains moving during these cold snaps.  One disabled switch at the wrong place and the wrong time during rush hours can paralyze entire branches and cause delays that can cascade for hours.

These switch heaters are a curious sight to many at first glance.  When many of the switch heaters are on, it literally looks like the switches are on fire and this can be alarming if you're the casual commuter glancing out the window on a cold morning.

Here are some photos of some of the LIRR's switch heaters at Jamaica during the recent storm that the MTA posted on their Facebook page:
(Photo Credit: MTA Facebook/Patrick Cashin)
(Photo Credit: MTA Facebook/Patrick Cashin)
(Photo Credit: MTA Facebook/Patrick Cashin)

These days on the LIRR, most switch heaters are electric. They are made up of high resistance metal bars that are bolted to the sides of the running rail. One end is grounded to the running rail and the other end is tied to the third rail through a knife switch in a little box.  Most are activated onsite, but there are some that are remote controlled.

The gas powered switch heaters are older and vestiges from an age when electric power was expensive and unreliable and gas was cheap.  The gas powered heaters would keep a place like Jamaica open even if electric power failed.   Today the gas heaters use natural gas that is provided by the utility companies (at one time they used manufactured gas from coal). The gas to these heaters is supplied by a one-and-a-half inch pipe with a globe valve down in a pit near the switch. A mechanic from the LIRR's Buildings and Bridges department turns on the gas and lights it with a fusee. Then the winds blow it out.

These days it is the gas heaters which are less than reliable; they blow out in high wind and have to be re-lit (a tricky task in the middle of rush hour)

The LIRR still also uses the really old "switch pots" which are filled with kerosene and burn a wick under the switch points. These are maintained by the track department. Trackmen work through the storms filling and lighting these.

And no story about switches and ice can be complete without mentioning "switch oil." To thaw out frozen switches, trackmen use Hexane, a hydrocarbon oil that is dumped along the rail from a long snouted can that looks like a flower watering can. Another trackman follows the first with a blazing broom that was soaked in the stuff which he uses to light up the oiled switches. The goop burns for fifteen minutes, effectively de-icing the frozen switch.

It is interesting to see how different crafts work on different heaters. Electric heaters are generally maintained by the signal department, oil pots by the Track Department, and gas heaters by the Building and Bridges Department.

In conclusion, switch heaters are a little-known but important piece of railroad infrastructure that keeps the switches switching  and the trains moving during the height of the winter.  The concept of switch heaters has been around for hundreds of years, and it is evidence of one of the many pieces of railroad technology that has been tried and tested and has lasted for over a century.  Without switch heaters much of the railroad would freeze along with the weather.  So next time you look out the window and see what looks like fire spreading across the tracks, don't be so quick to call the fire department to put them out!


  1. Now I'm curious how many switches are the modern electric sort, versus the obsolete gas sort, versus the even more obsolete oil pots.

    1. I am not sure of the exact figures, but I would presume that as interlockings have had their switches replaced due to various trackwork programs they have been given the new eletric heaters. Many of the switches around Jamaica still have the gas flames. I would presume only the very outer limits of the LIRR still have the old pots, but you never know.

  2. I wonder if the manufactured gas, which contained Carbon Monoxide and Hydrogen, ever caused problem with embrittlement.

    The natural gas flames look to be burning at slightly rich ratios, and could result in carbon and carbide buildup.

    Hexane isn't a goop unless it gets very cold (-137 F or less). Its very light; think gasoline but much thinner.

    1. Today, the gas is supplied directly by lines from the utility company (National Grid) so it wouldn't be much unlike the gas you get delivered to your home (if you get natural gas into your house).

      The hexane itself isn't a goop, the trackmen pour hexane down on the switch and then another trackman comes around with a broom that is doused with the oil they use to fill the switch pots. Together, they form a goop that can sit on the tracks and thaw the switches. Hexane itself is very volatile and will usually evaporate in less than a minute, which is why they come along with the flaming boom and make the "switch oil" that is pretty effective.


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