THROWDOWN MACHINE FOR TRAFFIC STUDIES 355 



MASTER CONTROL PANEL 



A master control panel for the throwdown machine is supplied on the 

 relay cabinet shown on Fig. 14. This panel provides: means for turning 

 the system on and off at the beginning and end of each day's operations; 

 a centralized alarm indicating system; a bank of marker action lamps 

 which indicate marker status during operation; and a present time 

 counter with a units-to-seconds conversion scale. 



The equipment operates on two battery supplies, one known as per- 

 manent battery and the other as day battery. Permanent battery is on 

 continuously during a complete throwdown run in order to hold operated 

 certain record relays. The day battery, however, is turned off diu-ing idle 

 periods. 



The equipment is arranged so that at the end of a working period all 

 operator functions requested by signal lamps during the last working 

 unit of time can be completed before the machine automatically stops. 

 This is controlled by the day-night switch which is turned to the night 

 position when it is desired to cease operation. The night lamp Ughts 

 at this time. When the operators have extinguished the last signal 

 lamp, the day power switch is turned to off. 



Certain critical portions of the machine are provided with alarm 

 circuits which automatically stop the machine and light lamps at the 

 control panel. In most cases, the lighting of one or more of these lamps 

 will require troubleshooting. When the trouble has been found, operation 

 of the key associated with the lamp extinguishes the lamp and permits 

 the machine to start again. 



results of throwdown studies 



The throwdown machine has now been in operation for slightly less 

 than four years. During this time 1383 seconds of equivalent central 

 office time, divided among eleven runs, have been accumulated. The 

 machine, of course, has not been in continuous operation, since the time 

 required for preparation of a run and eventual analysis of output data 

 exceeds the actual operating time for the run. In general, the same team 

 of girls has handled both preparation and analysis of data and operation 

 of the machine. Beyond this, there have been periods when no studies 

 were in progress. 



A detailed presentation of throwdo^vn results is not properly within 

 the scope of this article. However, a brief resume of the several runs with 

 some mention o^ their primary objectives and typical results is necessary 

 to conclude this picture of the throwdown machine. 



