Popular Science Montldi/ 



639 



Converting a Freight Car Into a 

 Wireless Station 



WHEN tlie United States troops 

 went into Mexico, they were 

 forced to meet a number of unusual 

 conditions. In Vera Cruz, for example, 

 they found new and difficult situations 

 and their ingenuity in overcoming some 

 of these hanflicaps is interesting. 



A train was 

 run twice 

 daily under a 

 flag of truce 

 from Vera 

 Cruz to the 

 interior. This 

 was always 

 accompanied 

 by a small 

 guard. Inas- 

 much as a 

 treacherous 

 attack upon 

 the cars was likely 

 it was considered 

 communication 



The exterior view of the car with aerial on top 



to occur at any tmie, 

 desirable to keep in 

 with the train. Since 

 this could not be accomplished in any 

 other way than by wireless, a complete 

 installation was made in one of the 

 passenger coaches. An upright was 

 erected at each end of tlic car, and aerial 

 wires were strung between cross-arm? 

 mounted upon 



these. The in- -~- ' ' 



struments 

 themselves 

 were placed 

 upon the 

 cusiiioned scats 

 within the car, 

 thus avoiding 

 difficulty from 

 vibration. The 

 ground connec- 

 tion was made 

 through the 

 trucks of the 

 car, and power 

 for the trans- 

 mitter was 

 supplied by a 

 small hand- 



when the latter was in motion. 



When the Arm\' landed, the Navy 

 men were relie\ed of guarding the city 

 and train, and the Signal Corps took 

 over the wireless work. A small gasoline- 

 driven motor-generator was placed on 

 the train, and the satisfactory work was 

 continued until the main railway line 

 was reopened and through trains began 



running be- 

 tween Vera 

 Cruz and 

 Mexico City, 

 some months 

 later. 



A new 

 Headquar- 

 ters station 

 was erected 

 on the roof of 

 the Terminal 

 Railway 

 Station, hav- 

 ing a four-wire umbrella antenna sup- 

 ported from a40-ft. pole, and maintnined 

 constant communication with all the 

 neighboring plants as well as with the 

 ships in the harbor. By use of the net- 

 work of wireless and buzzer-systems it 

 was possible for Headquarters to learn 

 instantly of conditions at all the outposts. 

 A narrow gage railway line connected 

 Vera Cruz with 



7 the detached 



post at EI 

 Tejar, about 

 nine miles 

 south, and the 

 train wireless 

 e<iuipment was 

 transferred to 

 cars run over 

 this division. 

 No passenger 

 coaches were 

 available, so a 

 framework 

 with a flat-top 

 aerial abov-e it 

 was built upon 

 one of the 

 springlcss flat- 

 cars. When the 

 was also train was still this worked well, but with 

 the cars in motion there was so much 



Interior view showing the apparatus in working order 

 power genera- 

 tor. A fixed radio station 

 installed at headquarters in Vera Cruz, 



and messages were exchanged between 

 this plant and that on the train, even 



vibration that a springboard was 

 ranged to support the apparatus. 



ar- 



