422 VALUATION, DEPRECIATION AND THE RATE-BASE 
TABLE 30. THE PROBABLE USEFUL LIFE OF VARIOUS 
ARTICLES (Continued) 
Description. pect] Residual Authority. Remarks. 
Years 
Distribution system 
street rallway...ooeeeneeenns 12} Cooley Milwaukee 3¢ Fare Case. 
street railway ............. 14 Starrett Milwaukee 3¢ Fare Case. 
distrib. and trans.......... 30.03 Wis. R. R. Com. Milwaukee 3¢ Fare Case. 
Ditches... da ae Salle miele 50 S.J. L. & P. Co: Cal. R. R. Com. rate hearing. 
concrete lining. ........... 20 S. J. L. & P. Co. Cal.R.R. Com. rate hearing. 
Economizers. ........---..... 10°20 Floy 4 Chicago Appraisals. 
15 Chi. U. T- Co. Chi. Union Trac. Co. Case. 
20 Stone & Webs. Chi. Union Trac. Co. Case. 
Electrical machinery 
dynamos and alternators. 25 Hammond Jour. Inst. Elec. E., 1907. 
dynamos and alternators. 30 8% Preece Report Bristol Corp., 1906. 
generators... ........oousre 10 Arbitrators Ata. St. Lgt. Controversy. 
generators. ..........ocxxos 15 St. LL. P. S.C. Union Elec. L. & P. Co. Case. 
Generators. .... ov vu-cnsrs 15 Chi. 0. T- Co. Chi. Union Trac. Co. Case. 
generators... ......c..cx-: 20 Stone & Webs. Chi. Union Trac. Co. Case. 
EENETAtOTS. . + « cisv sox an +» ij 15720 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
generators. ....c.oveoss 20 2¢1b. P.G.&E. Co. S. F. rate hearings, 1913-14. 
generators... ......c.-en-- 1 20 Arnold Coney Isl. & Brooklyn Case. 
ZENETALOTS. .. «vn eunrnscners 20 Floy 3rd Ave. Case, N. Y. City. 
generators. ..........noveee 20 S.J.L.&P.Cor Cal.R.R. Com. rate hearing. 
generators. ................ 13733 Trac. Val. Com. Chicago Con. Trac. Co. Case. 
generators, modern types..; 20 Wis. R. R. Com. Quoted by Henry Floy. 
generators, obsolete types.. Is Wis. R. R. Com. Quoted by Henry Floy. 
generators belted.......... 10-20 Chi. Trac. Com. Quoted by G. W. Cravens. 
generators direct conn....., 20 Chi. Trac. Com. Quoted by G. W. Cravens. 
generators, telephone plant’ 20 20% Wis. R. R. Com Wisconsin Tel. Co. Case. 
ATIOLOTS 0  alint sia atato fu didiniote 10 Arbitrators Ata. St. Lgt. Controversy. 
NOLOTBY Luin tiatainisis re mnwiotn= SEN OO Hammond Jour. Inst. Elec. Eng., 1907. 
TIIOLOTE + ole inten we win re of AE 25 9% Preece Report Bristol Corp., 1906. 
INOLOTS Lele lalate a fa) fal i mied 25 9% Parsons Jour. Inst. Elec. Eng., 1907. 
EOtars Larter LOE ool od 1D. P. G.& E. Co.  S. F. rate hearings, 1913-14. 
motors, modern types. .... 20 Foster “Eng. Valuation,” etc. 
motors, obsolete........... 15 Foster “ Eng. Valuation,” etc. 
motors, street railway. .... 20 Floy 3rd Ave. Case, N. Y. City. 
motors, street railway..... 20 Wis. R. R. Com Quoted by Henry Floy. 
motors, street railway. ... 30 Trac. Val. Com. Chi. Con. Trac. Co. Case. 
motors, small, misc....... 20 P. G.& E. Co. S. F. rate hearings, 1913-14. 
Engines. . atin rr 15 St. 1... B.'S. C. Union Elec. L. & P. Co. Case. 
20 Arbitrators Ata. St. Lgt. Controversy. 
25 Hammond Jour. Inst. E. E., 1907. 
engines and machinery... 25 6% Preece Report Bristol Corp., 1906. 
10-33% Chi. Trac. Com. Quoted by G. W. Cravens. 
13-20 Arnold Coney Isl. & Brooklyn Case. 
20-33} Arnold 4 Chicago Appraisals. 
15-20 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
20-33 Trac. Val. Com. Chicago Con. Trac. Co. Case. 
INACHINETY vss ova lels ia n'elels SE 2T, 67 Parsons Jour. Inst. Elec. E., 1907. 
stent ra RT Chi. U.T. Co. Chi. Union Trac. Co. Case. 
SECRTIY. «ve a visa ein alee wieleinins SER 20 Stone & Webs. Chi. Union Trac. Co. Case.