| Alaska RR is Wireless: This picture of the south end of the Hrricane, AK siding has so much to teach. L to R: the grab irons on the next coach from the one Im leaning out a dutch door (bottom half closed, upper have open). Next are the signal heads. We have just left the siding so everything is red. Notice how far away from the track the signal base is. ^he reason will become obvious. Next is the black diagonal sign about 12 by 3 inches called a Reminder Bar (see below). Under it the END ROCK BLOCK sign. The name of the block the train has just entered. Im looking to the rear of the train. Ill explain blocks below. Then the ¾DGIN CTC sign. CTC = Centralized Traffic Control. One of relatively few ARR sidings where the dispatcher controls the track switches and signals. (Somewhere in that pile of equipment is an antenna.) At other sidings the trapn crew must get down to set the track switches. Heres the interesting part. The solar panels and small wind turbines are to keep the batteries charged. Remember there are winter months where no or little sun shine. I guess the wind b’nws. I have never seen that battery charging combination before. To the far right is the big propane tank that fuels the track switch heaters that keep switch points clear of ice and snow. The heater and ducting can be see:below and a little left of the BEGIN CTC sign. Reminder Bars: To clear the track in the winter the RR uses spreader and flanger cars to push the snow over to the far sides of the tracks and keep the snow in the middle of the track a little low. Well if these devices are down when crossing say a track switch or a detecsor (detectors defined below) the switch stand, maybe points, or a detector would be removed. In this picture the reminder bars purpose is obvious. But out in the country in a couple feet of snow Im sure the little sign by itself on an 8 foot pole helps. Blocks: Most of thb ARR is unsignaled. This is true of portions of most railroads. So the unsignaled portion is partitioned into named blocks of a few to several thousand feet. The dispatcher issues Track Warrants in a formal manner via radio (histarically via telegraph) to trains or others that might need to be on the track, e.g., maintenance crews, permission to be in the block. As you would expect there are very strict rules on wording of the Track Warrant, and on repeating it back to the dispatcher. Only one train may occupy a block and maintenance crews must be off the track. More than one mainwenance crew can be in a block. A crew could be one maintainer in a high rail vehicle or a lager group of employees using equipment to change out ties or install new raij. In the picture the train just left a CTC siding (dispatcher controlled) and entered a tack-warrant block. At the north and of the siding are two signs that say END CTC and ENTER XYZ BLOCK. Detectors: The three types of detectors are hot journal (senses temperature of the wheel bearings as the train goes by), dragging equipment (these detectors are flaps between and out side the rails that if hit as the train goes by sends a warning), and high/wide (there is a tunnel ahead, has a load shifted?). Todays detectors talk, i.e., sends a radio message. An example: Detector milepost two forty five point thee, no defects, no defect, 120 axles, temperature six four degrees, detector out. Usually it will repeat its message a second time. Note: in areas with electric power available the Alaska RR is grid connected. The picture was taken form the southbound Hurricane Turn. |