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Scanner Radios & Frequencies






Introduction

Many people have asked us about the use of radios by railroads and how riders and fans can use scanner radios to "listen in". This section of ON TRACK ON LINE discusses these topics.



AAR Channel Numbering System

The American Association of Railroads has assigned channel numbers to each of 96 radio frequencies in the 160-161 MegaHertz bands. These frequencies are used in the United States and Canada. Channels 7-96 are used in the U.S. for railroad operations. Channels 2-6 are used in Canada for rail operations only. In the U.S. channels 3-6 are used by railroads for truck operations.

The following table converts from AAR channel number to the appropriate radio frequency (MHz).

Ch Frequency Ch Frequency Ch Frequency Ch Frequency
02 159.810 26 160.500 50 160.860 74 161.220
03 159.930 27 160.515 51 160.875 75 161.235
04 160.050 28 160.530 52 160.890 76 161.250
05 160.185 29 160.545 53 160.905 77 161.265
06 160.200 30 160.560 54 160.920 78 161.280
07 160.215 31 160.575 55 160.935 79 161.295
08 160.230 32 160.590 56 160.950 80 161.310
09 160.245 33 160.605 57 160.965 81 161.325
10 160.260 34 160.620 58 160.980 82 161.340
11 160.275 35 160.635 59 160.995 83 161.355
12 160.290 36 160.650 60 161.010 84 161.370
13 160.305 37 160.665 61 161.025 85 161.385
14 160.320 38 160.680 62 161.040 86 161.400
15 160.335 39 160.695 63 161.055 87 161.415
16 160.350 40 160.710 64 161.070 88 161.430
17 160.365 41 160.725 65 161.085 89 161.445
18 160.380 42 160.740 66 161.100 90 161.460
19 160.395 43 160.755 67 161.115 91 161.475
20 160.410 44 160.770 68 161.130 92 161.490
21 160.425 45 160.785 69 161.145 93 161.505
22 160.440 46 160.800 70 161.160 94 161.520
23 160.455 47 160.815 71 161.175 95 161.535
24 160.470 48 160.830 72 161.190 96 161.550
25 160.485 49 160.845 73 161.205 97 161.565

Note that these frequencies are not the only frequencies used by railroads. Some railroads also use frequencies in the 4xx.xxx MegaHertz band, particularly around 45x.xxx, 46x.xxx, and 47x.xxx.

Most official railroad radios that synthesize the frequencies have a window that shows the AAR channel number for transmitting and the AAR channel number for receiving. For example, Amtrak's primary Road frequency in the Northeast Corridor is 160.920 MHz, Channel 54. The window on the railroad radio would show 5454 (transmit on AAR channel 54 and receive on AAR channel 54).

Railroads also use some frequencies to transmit end of train telemetry. Some EOT devices, for example, transmit the train's brake pressure to the closest tenth of a pound and whether the EOT is moving or not every 40 seconds or whenever there is a change. AAR has allocated 457.9375 MHz and 452.9375 for EOT telemetry with the latter used at the head end to transmit control signals. Most railroads use these frequencies.

Since EOT devices transmit at two watts, the transmission will travel about 3 to 5 miles. Thus, by setting your scanner to scan these EOT frequencies, you get a warning whenever a train approaches. The problem with this strategy, of course, is that as soon as your scanner picks up anything on 457.9375 or 452.9375, it will lock on that channel. Thus, this strategy works best if your scanner makes it easy to change the channels that are scanned so that you can stop scanning 457.9375/452.9375 when you know a train is close.



Using a Scanner Radio

When you use a scanner radio to listen to railroad frequencies you will hear:

  • Conversations among the train crew members.

  • Conversations between dispatchers and train's "head end" (engineers).

  • "Talking defect detectors" which will usually announce "no defects". Some of them will also tell you the train's speed, or the number of axles the train has, or even the outside air temperature.

Some methods for using a scanner radio:

  • If your scanner has the ability to scan a range of frequencies, you could set your scanner to scan the range 159.810 to 161.565 MHz.

  • If you have a scanner that is capable of storing 100 channels of frequencies, you could enter all of the AAR frequencies in their corresponding channels (the frequency for AAR channel 36 in scanner channel 36, for example). Then you can use the channel lock-out facility of most scanners to only scan the desired frequencies. This saves you from the need to reenter frequencies when you change railroads or locations -- simply change which channels are locked out.

  • You can preset all the local frequencies into one or two "banks" (typically 10 or 20 scanner channels) of your scanner and scan through all of them. Sometimes "all the local frequencies" may be only a few. You may wish to set one of them as your "Priority" channel, to be checked every second or two even if the scanner is locked on another active transmission.

  • If you don't know the local road frequency (for example), but can talk to someone with access to a railroad radio, simply ask them to tell you what numbers show in the window. If they tell you, for example, it shows 3666, then you know that they are transmitting on 160.650 (Chan 36)and receiving on frequency 161.100 (Chan 66) and can set your scanner accordingly.

Once you've used your scanner for a while, you'll think of other methods.

Hint: Use an earphone or earphones. It's much easier to hear your scanner with an earphone, and if you are traveling on a passenger train an earphone is required.

LAWS: The use of scanner radios is governed by federal laws and regulations, and various state laws. A summary listing can be fouund here. The details can be found at the Scanner Reference Laws, Rules and Regulations web site.



Selecting a Scanner Radio

Features

Here are some features to look for when selecting a scanner radio for scanning railroad frequencies:

  • Capable of receiving in the 148-174 MHz "High Band" and the 450-470 MHz "UHF Band".
  • Sufficient pre-storable scanner channels to cover all frequencies you will wish to listen to regularly (see below).
  • A lock-out button to allow selected scanner channels to be locked out (not scanned).
  • A priority system and button to allow selected scanner channels to be indicated as high priority for scanning.
  • A search capability to allow for search for active frequencies within some range.
  • A delay button which holds the current frequency for 1 or 2 seconds after a signal ends.
  • A button-controlled light for the frequency information window.
  • A lock for the keypad to prevent accidental key presses.
  • Rechargeable batteries

Number of Channels

Scanners are available that have 10, 20, 50, 100, 200, 300 and even more pre-storable channels. These are internal channels that the user can select and punch a frequency into, after which the frequency is permanently stored in that channel (until you change it). The more channels the more expensive the scanner, of course.

For railroad scanning, 20 scanner channels is usually adequate, but 100 scanner channels is much more flexible since then the 96 AAR frequencies can be pre-set, as discussed in the Using a Scanner Radio section. 200 channels adds even more flexibility as the 96 AAR frequencies can be pre-set, and other banks of frequencies for particular areas can be pre-set, including areas that don't comply with the AAR scheme (several transit systems, Canadian railroads, FRS channels).

Brand Names

The primary brand names for hand-held scanners suitable for scanning railroad frequencies are Radio Shack and Bearcat, both made by Uniden America Corporation. In general, the Radio Shack models are more expensive, but there are far fewer stores that carry Bearcat scanners. Bearcat scanners are readily available by mail order however. Other brands can be found at electronic supply outlets also.



Antennas

The best scanner radio that money can buy is worthless without an antenna. But often the antenna that comes with the scanner (usually called a "rubber ducky") is hardly better than no antenna, particularly inside a steel vehicle or in an area of poor reception such as a city, valley, dense forest, and so on. The best way to improve the performance of your scanner is to improve the antenna you use.

Although convenient to use, rubber duckies and base station whips are short, not optimized for railroad frequencies and cannot be moved to the best position without moving the scanner. Longer antennas, adjustable whips, and (for indoor base units) a wall-mounted antenna can be a major improvement.

Rubber duckies are actually "loading coils" -- a coil of wire used to effectively lengthen the electronic length of an antenna without increasing it's physical length. The electronic length of an antenna is critical to it's performance, but only a variable length antenna is correct for many different frequency bands. So one important improvement over rubber duckies is an adjustable whip, usually with a small loading coil near the bottom. Antennas of this type which will connect directly to scanners are available at Radio Shack and many electronic supply shops.

To tune an adjustable whip the following formula governs:

Correct length (inches) = 2,800 / frequency in MegaHertz
(where "/" means divide)

Let's look at the former Conrail's main road frequency, roughly in the middle of the railroad band:

length = 2800 / 160.800 = 17.4

So, a 17.4 inch antenna will optimize reception (anything within about 1/2 inch will do). Note that this is a "quarter-wave" antenna -- one quarter of the wavelength for that frequency. This quarter-wave 17.4 inch antenna will work pretty well across the entire AAR Channel range listed above.

If your antenna isn't adjustable, you can get the same result by trimming or shortening the antenna with wire cutters. Be sure to measure carefully! Usually you can cut from the bottom of a fixed length antenna, depending on how the bottom is configured. Sometimes it's only feasible to cut from the top. Some sort of protective item should be attached to the top in that case. It will have little effect on performance. A styrofoam ball glued on is one possibility.

Another thing that can be done to improve performance is to use a "ground plane". Actually the antenna one sees is only half of a true antenna. An electrical ground is the other. Without a ground an antenna cannot work well; with a ground plane the improvement can be considerable. Good ground planes are:

  • metallic objects roughly flat
  • the earth itself

For a portable scanner, the best that can usually be done is to position the scanner on a metallic object such as an vehicle hood or roof, roadside guardrail, or pipeline standpipe. The latter is probably best since it makes the best electrical ground. Obviously the scanner should be removed from any sort of leather/leatherette case. The plastic case of the radio reduces the effect but doesn't eliminate it.



Frequencies

There are several sources for lists of frequencies used by North American railroads.

  • The Compendium of American Railroad Radio Frequencies, a Kalmbach Publishing book, while now out of print is available at some railroad hobby shops. Get the 15th or later edition. This has been the 'bible" for railroad frequencies, though the final edition is beginning to become outdated.
  • Rail Radio Online-Frequencies Self-described as "...a growing database of railroad frequencies." More up-to-date in some areas than some of the other sites listed here.
  • Gary L. Sturm's RR Radio Frequency Links Gary is co-author of the Compendium book above.
  • Railfan Timetables are available from Altamont Press that cover the western states (Rocky mountains and west) and that include detailed information about frequencies used by all the railroads in there areas.
  • Employee Timetables are often available at railroad swap meets; these also contain detailed frequency info; even if a few years out of date the frequency information is often still current.
  • Railroad Radio is available from California Transit Publications for $19.95. It's 208 pages is packed with information on railroad radio communications and systems, including in-depth coverage of radio scanners and accessories. Address: California Transit Publications, PO Box 6427, Whittier, CA, 90609. This book does not contain frequency lists.
  • North American railroad frequencies web site. Maintains lists of frequencies for most railroads.
  • Scanning Reference Extensive information about scanner radios and their use with links to frequency lists organized several different ways.

Amtrak trains use the frequencies of the Host Railroad over which they are running. Our Amtrak Frequencies Page lists the frequencies Amtrak uses on each of its routes.



Family Radio Service Channels and Frequencies

FRS is a private, two-way, very short-distance voice communications service for facilitating family and group activities. FCC license is not required. Amtrak On-Board Service personnel will be using this system on some trains. Frequencies will be taken from the following authorized list, with no prior frequency assignment. Most scanners are capable of receiving these frequencies.

Channel Frequency Channel Frequency
1 462.5625 8 467.5625
2 462.5875 9 467.5875
3 462.6125 10 467.6125
4 462.6375 11 467.6375
5 462.6625 12 467.6625
6 462.6875 13 467.6875
7 462.7125 14 467.7125




GPS

Also learn about the use of a Global Positioning System (GPS) receiver on a train on our GPS Train Tracking page.

More information

For more information on this topic or to make suggestions for additions or corrections to this page, you may contact .

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