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Total energy and labor requirements for an electric commuter railroad
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0wk5442t7mo1-0539/$02.0010 Printi in Grcal Briain
TOTAL ENERGY AND LABOR REQUIREMENTS FOR AN ELECTRIC COMMUTER RAILROAD PETER S. PENNER Research Engineer, Energy Research Group, Center for Advanced Computation, University of Illinois at Urbana-Champaign, Urbana, IL 61801,U.S.A. (Received 28 November 1977)
Abstrarz-Input-output analysis is used to examine an electric commuter railroad operating out of New York City, U.S.A., in 1971. The direct and indirect energy costs of propulsion, station operation and rail-plant investments are all computed per passenger-mile of travel. A similar analysis is conducted to determine direct and indirect employment generated per passenger-mile. Results show that, with electricity valued at 11,032Btu/kWh, commuter rail travel required 9900Btu and 8.5 millionths of a job per passenger-mile.
INTRODUCTION
Among the many issues facing urban policymakers is the problem of providing cheap, adequate transportation within metropolitan areas. Cheap energy and a patchwork of transport policies have led to a steadily worsening combination of several modes as different as bicycles and commuter railroads. As jobs, money and energy grow more scarce and cities grow more congested, policymakers will be forced to evaluate the costs and benefits of each competing mode. The obvious first step in such a process is the accurate and complete accounting for each mode of the most important characteristics, including cost, energy use and employment impact. Towards this end, we comput the direct and indirect energy and labor costs for a major commuter railroad. Much research has been done along these lines, and it has generated more than its share of controversy at all levels of government. Some of the earliest modern transportation-energy studies were those of H&t,’ Mooz’ and Herendeen and Sebald.3 The early investigators studied only the direct energy used by major transport modes, that is, the energy used by the vehicles in energy form. These studies were followed by others on more obscure modes with more vehicle detail and more complete systems.c9 Government-transit agencies and private transit organization now both routinely study energy costs for their systems.” The most complete compendium of transit studies to date can be found in a recent report by the Congressional Budget O&e.” Most of these studies consider direct energy use by the vehicle, while a few account incompletely for indirect energy use. Indirect energy refers to the energy consumed throughout the economy to supply the goods and services (including the delivered energy) needed to perform a given operation. For the railroad, indirect energy is consumed in supplying traction power, office supplies, maintenance and repair materials, etc. In addition, the energy cost of all rail-plant investments is amortized over the actual useful life of the item and becomes a component of indirect usage. The only practical and complete way of measuring indirect energy use is input-output modeling (I/O). Here we use the University of Illinois’ 357-order energy input-output model as described elsewhere. ‘**13 Readers unfamiliar with this technique are encouraged to consult Refs. 12 and 13. Unless noted here, total energy costs are derived from standard 1%3 primary energy intensities’* applied to 1971 dollar amounts and deflators from the National Income and Product Accounts.” Units of energy are the Btu. To facilitate comparison with other transit modes, all costs will be normalized by the total number of passenger-miles (PM) of service provided by the railroad. Normalization by passenger-miles, the movement of one passenger one rail mile, has the disadvantage of being very sensitive to the historic load factor of the railroad. Nevertheless, it provides the best means of comparison between transit operations as they now stand. 539
PETERS. PENNER
540 RAILROAD
CHARACTERISTICS
The Port Authority Trans-Hudson Corporation, PATH, is a semi-private corporation chartered jointly by the states of New York and New Jersey for the purpose of managing certain interstate transportation facilities. One of these facilities is the PATH system, an all-electric commuter railroad carrying about seventy-six thousand riders, daily between seven points in New Jersey and six stations in Manhattan. It has experienced most of the problems common to the so-called heavy rail transportation mode, namely, increased competition from the automobile, budget deficits, fare-hike disputes, etc. The managers of PATH claim to have the worst peaking (rush-hour) characteristics of any commuter railway in the U.S. The average load factor drops to 8 passengers per car off-peak from an on-peak high of about 100.15A map of the present PATH system is shown in Fig. 1. The railroad had a 1971 annual budget of 23 million dollars and employs 1162 people. Operating revenues account for about twelve million dollars, leaving a 17 million dollar budget deficit in 1971. PATH controls a total of 35 miles of track: the actual interstation track distance is 13.87 miles.16 Very few passenger railroads collect data on passenger-miles; PATH has stated officially that it does not. However, PATH has studied its passenger trafhc in some detail and has the figures on many closely-related quantities such as trip length. A simple estimate of annual passenger miles on business days can be made as follows:” 143,680(pass./day) x (5 miles avg. trip) x (260 dayslyr.) = 1.88 x 10’ pass.-mi./yr. Officials in the PATH system state that weekend trips account for about 8% of total.‘* Assuming the same average trip length, (1.88 x 108)(1.08) = 2.03 x 10’ total pass.-mi./yr. for the PATH system in 1971.
Newark
m
Part Authority Trane- Hudran System
Fig. 1. Port authority bans-Hudson (PATH) system.
Total energy and labor requirements for an electric commuter railroad
541
ENERGY USE
PATH is an all-electric railroad, and uses no other form of energy except natural gas for heating its station. Neglecting the latter, PATH’s direct energy use can be found from railroad statistics on traction-power consumption. This power is purchased directly from Consolidated Edison and delivered on high-voltage lines. It is likely that these lines reduce the line losses associated with this power below the average levels implied in the aggregate energy intensity of electric power. Thus, the primary energy content of PATH direct energy use is expected to be a slight overestimate, a conservative assumption from the policy standpoint. In 1971, total PATH traction power consumption was 62,597,OOO kWh,” which represents 8.3 x 10” Btu of primary energy. PATH’s indirect energy consumption is calculated by using input-output analysis. The energy may be calculated as follows: energy (lo6 Btu) = $ $k(TOINBPh + 2 $[O.B(TOINBP), + 0.0121, =I I=1 where j is an industrial good purchased at the wholesale level and k is a consumer item purchased as final demand. Most items required use of the second summation term. Goods, services and investments purchased by the PATH system are reported by Ref. 16. Several inputs to the PATH system were found to be purchases of goods normally considered consumer goods sold to final demand. However, PATH purchases many of these items in bulk and, therefore, not at consumer price levels. Since I/O is geared to accommodate only purchases to final demand, the following equation was employed for these expenditures:
EnergY+ti = (expenditurei)[O.B(I/O codei) + 0.2(0.06)]. Units: Btu x lo6 $1%3 lo6 Btu/$l%3 lo6 Btu/$1%3 The actual numerical values in the above formula (with the exception of the latter) are non-dimensional and reflect the relative amounts of production and retailing dollar flows; the purchaser’s price-margin breakdown and the energy intensity for the margin were estimated. In all calculations, consumer and/or industrial deflators were used where appropriate. The results show indirect energy use for the PATH system totalling 1.8 x 10” Btu of primary energy. This result resembles findings on other transport modes, which show approximately equal direct and indirect energy use. Total primary energy consumption for the PATH system in 1971 was 2.01 x lo’* Btu primary, 10.6% direct. LABOR INTENSITY
PATH reports a total work force of 1162 employees, approximately all full time.16 This represents a direct labor intensity of 5.72 x 10e6jobs/PM. Indirect labor intensity is computed by precisely the same technique as for indirect energy except that I/O labor coefficients (units jobs per 1%3 dollar) are applied. Results show an indirect labor intensity of 2.82 x 10d jobs/PM (573 jobs). Total labor intensity for PATH railway travel in 1971 is the sum of direct and indirect intensities, 8.54 x low6jobs/PM. RESULTS
AND CONCLUSION
Calculations have shown that the total energy intensity of PATH commuter travel is 9980 Btu/PM (10.6% direct). This result may be compared with urban cars at 8900 Btu/PM (1.9 people/car) and urban buses at 5300 Btu/PM’ (about 2&25% full). The rail-energy disadvantage is due to the fact that electric railways utilize electric energy delivered at a conversion efficiency (primary energy input to electricity output) of only 28% and have extremely poor load factors. Normally, because of its relatively low rolling and air resistance, rail enjoys a lower energy cost than other modes. Employment generated by PATH passenger travel is a definite benefit of this mode. The total labor intensity of 8.5 x 10” jobs/PM compares nicely with urban bus travel (with approximately the same load factor) at 8.3 x 10d jobs/PM and is more than double all other urban
542
PETERS. PENNER
modes, including automobiles (4.2 x 1O-6jobs/PM).4 However, as ridership increases and energy cost per passenger mile goes down, this mode will lose some of its employment advantages. Findings similar to these for the BART medium-rail transit system in San Francisco caused great controversy. They should not be shocking to anyone acquainted with the facts. The value of rail travel is clearly in the movement of large volumes of people (or goods) over long distances at moderate speeds. An average load factor of 8 persons per car is nowhere near large enough to take advantage of rail economies of scale. On the other hand, no mode can even approach the speed and carrying capacity of this system during peak periods. Resolving this dilemma, given the large investment already made in the system, calls for innovative policymaking. One possibility could be a shutdown of rail operations during off-peak periods, with small buses operating along nearly identical routes as a more efficient replacement. It will be interesting to watch the change in urban transit pattern as cities and urban citizens adjust to more costly energy and new transit priorities. Acknowledgements-l would like to thank Mr. Warren B. Lovejoy, Chief, Central Research and Statistics Division, PATH Corp., for invaluable cooperation. I would also like to thank Bruce Hannon. Bob Herendeen and James Tripp for moral and technical support and Marcie Howell and Veronica Soltys for preparation of the manuscript.
REFERENCES 1. E. Hirst. Energy Intensioeness of Passenger and Freight Transport Modes, 1950-70,Oak Ridge National Laboratory, Oak Ridge, Tennessee, ORNL-NSF-EP-44 (April 1973). 2. W. E. Mooz, The Efecf of Fuel Price Increases on Energy Intensiveness of Freight Transport, Rand Corporation, Santa Monica, California, R&s-NSF (Dec. 1971). 3. A. Sebald and R. A. Herendeen, The Dollar, Energy and Employment Impacts of Air, Rail and Automobile Passenger Transportation, Center for Advanced Computation, University of Illinois, Urbana, Illinois, CAC Document % (Sept. 1974).Reprinted in The Energy Conservation Papers (Edited by Robert H. Wiiiams), Chap. 3. Ballinger, Cambridge, Mass. (1975). 4. B. Hannon and F. Puleo, Transfeting from Urban Cars to Buses: The Energy and Employment Impacts, Center for Advanced Computation, University of Ilhnois, Urbana, Illinois, CAC Document 98 (April 1974). Reprinted in The Energy Conseroation Papers, (Edited by Robert H. Williams), Chap. 3. Ballinger, Cambridge, Mass. (1975). 5. A. C. Masey and R. L. Paullin, Transportation Vehicle Energy Infensities (A Joinr DOT/NASA Reference Paper), NASA Ames Research Center and DOT, Moffett Field, California (20 June 1974). 6. D. B. Shot&a, Transpotiation Enegy Consetxation Data Book: 2nd Edition. Oak Ridge National Laboratories, oak Ridge, Tennessee, ORNL-5320(Oct. 1977). 7. Colloquium of Energy and Patterns of Human Settlement, 2 March 1977, Center for Urban and Regional Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514. 8. A. K. Meier, Tech. Rev. 79, 3 (1977). 9. Energy and the Automobile, Socitey of Automative Engineers, New York, SP-383 (July 1973). IO. M. J. Bernard, Enuironmenral Aspects of a Large Transit Operation, Regional Transit Authority, Chicago, Illinois, TRJS-01 (Nov. 1975). II. Urban Transportation and Energy: The Potenbal Sauings of Different Modes, Congressional Budget Office, Serial No. 95-8 (Sept. 1977). 12. R. A. Herendeen, An Energy Input-Output Matrix for the United States, l%3: User’s Guide, Center for Advanced Computation, University of Illinois, Urbana, IL 61801,CAC Document 69 (March 1973). 13. C. W. Bullard, III and R. Herendeen, Energy Cost of Consumer Goods 1%3/67, Center for Advanced Computation, University of Illinois, Urbana, Illinois, CAC Document I40 (Nov. 1974).Reprinted in Energy Policy, Dec. 1975. 14. Survey of Current Business, U.S. Department of Commerce, July issue. various years. IS. PATH Corp., letter to Environmental Defense Fund, 5 Feb. 1974. 16. PATH Corp., Annual Report. year ending 31 Dec. 1971. 17. PATH Corp. Reply to Motion of Intervenor, ICC. 1 t S No. 8875. I7 Oct. 1973,with 3 attachments. 18. PATH Corp., letter to the author, 23 Jan. 1975.
0wk5442t7mo1-0539/$02.0010 Printi in Grcal Briain
TOTAL ENERGY AND LABOR REQUIREMENTS FOR AN ELECTRIC COMMUTER RAILROAD PETER S. PENNER Research Engineer, Energy Research Group, Center for Advanced Computation, University of Illinois at Urbana-Champaign, Urbana, IL 61801,U.S.A. (Received 28 November 1977)
Abstrarz-Input-output analysis is used to examine an electric commuter railroad operating out of New York City, U.S.A., in 1971. The direct and indirect energy costs of propulsion, station operation and rail-plant investments are all computed per passenger-mile of travel. A similar analysis is conducted to determine direct and indirect employment generated per passenger-mile. Results show that, with electricity valued at 11,032Btu/kWh, commuter rail travel required 9900Btu and 8.5 millionths of a job per passenger-mile.
INTRODUCTION
Among the many issues facing urban policymakers is the problem of providing cheap, adequate transportation within metropolitan areas. Cheap energy and a patchwork of transport policies have led to a steadily worsening combination of several modes as different as bicycles and commuter railroads. As jobs, money and energy grow more scarce and cities grow more congested, policymakers will be forced to evaluate the costs and benefits of each competing mode. The obvious first step in such a process is the accurate and complete accounting for each mode of the most important characteristics, including cost, energy use and employment impact. Towards this end, we comput the direct and indirect energy and labor costs for a major commuter railroad. Much research has been done along these lines, and it has generated more than its share of controversy at all levels of government. Some of the earliest modern transportation-energy studies were those of H&t,’ Mooz’ and Herendeen and Sebald.3 The early investigators studied only the direct energy used by major transport modes, that is, the energy used by the vehicles in energy form. These studies were followed by others on more obscure modes with more vehicle detail and more complete systems.c9 Government-transit agencies and private transit organization now both routinely study energy costs for their systems.” The most complete compendium of transit studies to date can be found in a recent report by the Congressional Budget O&e.” Most of these studies consider direct energy use by the vehicle, while a few account incompletely for indirect energy use. Indirect energy refers to the energy consumed throughout the economy to supply the goods and services (including the delivered energy) needed to perform a given operation. For the railroad, indirect energy is consumed in supplying traction power, office supplies, maintenance and repair materials, etc. In addition, the energy cost of all rail-plant investments is amortized over the actual useful life of the item and becomes a component of indirect usage. The only practical and complete way of measuring indirect energy use is input-output modeling (I/O). Here we use the University of Illinois’ 357-order energy input-output model as described elsewhere. ‘**13 Readers unfamiliar with this technique are encouraged to consult Refs. 12 and 13. Unless noted here, total energy costs are derived from standard 1%3 primary energy intensities’* applied to 1971 dollar amounts and deflators from the National Income and Product Accounts.” Units of energy are the Btu. To facilitate comparison with other transit modes, all costs will be normalized by the total number of passenger-miles (PM) of service provided by the railroad. Normalization by passenger-miles, the movement of one passenger one rail mile, has the disadvantage of being very sensitive to the historic load factor of the railroad. Nevertheless, it provides the best means of comparison between transit operations as they now stand. 539
PETERS. PENNER
540 RAILROAD
CHARACTERISTICS
The Port Authority Trans-Hudson Corporation, PATH, is a semi-private corporation chartered jointly by the states of New York and New Jersey for the purpose of managing certain interstate transportation facilities. One of these facilities is the PATH system, an all-electric commuter railroad carrying about seventy-six thousand riders, daily between seven points in New Jersey and six stations in Manhattan. It has experienced most of the problems common to the so-called heavy rail transportation mode, namely, increased competition from the automobile, budget deficits, fare-hike disputes, etc. The managers of PATH claim to have the worst peaking (rush-hour) characteristics of any commuter railway in the U.S. The average load factor drops to 8 passengers per car off-peak from an on-peak high of about 100.15A map of the present PATH system is shown in Fig. 1. The railroad had a 1971 annual budget of 23 million dollars and employs 1162 people. Operating revenues account for about twelve million dollars, leaving a 17 million dollar budget deficit in 1971. PATH controls a total of 35 miles of track: the actual interstation track distance is 13.87 miles.16 Very few passenger railroads collect data on passenger-miles; PATH has stated officially that it does not. However, PATH has studied its passenger trafhc in some detail and has the figures on many closely-related quantities such as trip length. A simple estimate of annual passenger miles on business days can be made as follows:” 143,680(pass./day) x (5 miles avg. trip) x (260 dayslyr.) = 1.88 x 10’ pass.-mi./yr. Officials in the PATH system state that weekend trips account for about 8% of total.‘* Assuming the same average trip length, (1.88 x 108)(1.08) = 2.03 x 10’ total pass.-mi./yr. for the PATH system in 1971.
Newark
m
Part Authority Trane- Hudran System
Fig. 1. Port authority bans-Hudson (PATH) system.
Total energy and labor requirements for an electric commuter railroad
541
ENERGY USE
PATH is an all-electric railroad, and uses no other form of energy except natural gas for heating its station. Neglecting the latter, PATH’s direct energy use can be found from railroad statistics on traction-power consumption. This power is purchased directly from Consolidated Edison and delivered on high-voltage lines. It is likely that these lines reduce the line losses associated with this power below the average levels implied in the aggregate energy intensity of electric power. Thus, the primary energy content of PATH direct energy use is expected to be a slight overestimate, a conservative assumption from the policy standpoint. In 1971, total PATH traction power consumption was 62,597,OOO kWh,” which represents 8.3 x 10” Btu of primary energy. PATH’s indirect energy consumption is calculated by using input-output analysis. The energy may be calculated as follows: energy (lo6 Btu) = $ $k(TOINBPh + 2 $[O.B(TOINBP), + 0.0121, =I I=1 where j is an industrial good purchased at the wholesale level and k is a consumer item purchased as final demand. Most items required use of the second summation term. Goods, services and investments purchased by the PATH system are reported by Ref. 16. Several inputs to the PATH system were found to be purchases of goods normally considered consumer goods sold to final demand. However, PATH purchases many of these items in bulk and, therefore, not at consumer price levels. Since I/O is geared to accommodate only purchases to final demand, the following equation was employed for these expenditures:
EnergY+ti = (expenditurei)[O.B(I/O codei) + 0.2(0.06)]. Units: Btu x lo6 $1%3 lo6 Btu/$l%3 lo6 Btu/$1%3 The actual numerical values in the above formula (with the exception of the latter) are non-dimensional and reflect the relative amounts of production and retailing dollar flows; the purchaser’s price-margin breakdown and the energy intensity for the margin were estimated. In all calculations, consumer and/or industrial deflators were used where appropriate. The results show indirect energy use for the PATH system totalling 1.8 x 10” Btu of primary energy. This result resembles findings on other transport modes, which show approximately equal direct and indirect energy use. Total primary energy consumption for the PATH system in 1971 was 2.01 x lo’* Btu primary, 10.6% direct. LABOR INTENSITY
PATH reports a total work force of 1162 employees, approximately all full time.16 This represents a direct labor intensity of 5.72 x 10e6jobs/PM. Indirect labor intensity is computed by precisely the same technique as for indirect energy except that I/O labor coefficients (units jobs per 1%3 dollar) are applied. Results show an indirect labor intensity of 2.82 x 10d jobs/PM (573 jobs). Total labor intensity for PATH railway travel in 1971 is the sum of direct and indirect intensities, 8.54 x low6jobs/PM. RESULTS
AND CONCLUSION
Calculations have shown that the total energy intensity of PATH commuter travel is 9980 Btu/PM (10.6% direct). This result may be compared with urban cars at 8900 Btu/PM (1.9 people/car) and urban buses at 5300 Btu/PM’ (about 2&25% full). The rail-energy disadvantage is due to the fact that electric railways utilize electric energy delivered at a conversion efficiency (primary energy input to electricity output) of only 28% and have extremely poor load factors. Normally, because of its relatively low rolling and air resistance, rail enjoys a lower energy cost than other modes. Employment generated by PATH passenger travel is a definite benefit of this mode. The total labor intensity of 8.5 x 10” jobs/PM compares nicely with urban bus travel (with approximately the same load factor) at 8.3 x 10d jobs/PM and is more than double all other urban
542
PETERS. PENNER
modes, including automobiles (4.2 x 1O-6jobs/PM).4 However, as ridership increases and energy cost per passenger mile goes down, this mode will lose some of its employment advantages. Findings similar to these for the BART medium-rail transit system in San Francisco caused great controversy. They should not be shocking to anyone acquainted with the facts. The value of rail travel is clearly in the movement of large volumes of people (or goods) over long distances at moderate speeds. An average load factor of 8 persons per car is nowhere near large enough to take advantage of rail economies of scale. On the other hand, no mode can even approach the speed and carrying capacity of this system during peak periods. Resolving this dilemma, given the large investment already made in the system, calls for innovative policymaking. One possibility could be a shutdown of rail operations during off-peak periods, with small buses operating along nearly identical routes as a more efficient replacement. It will be interesting to watch the change in urban transit pattern as cities and urban citizens adjust to more costly energy and new transit priorities. Acknowledgements-l would like to thank Mr. Warren B. Lovejoy, Chief, Central Research and Statistics Division, PATH Corp., for invaluable cooperation. I would also like to thank Bruce Hannon. Bob Herendeen and James Tripp for moral and technical support and Marcie Howell and Veronica Soltys for preparation of the manuscript.
REFERENCES 1. E. Hirst. Energy Intensioeness of Passenger and Freight Transport Modes, 1950-70,Oak Ridge National Laboratory, Oak Ridge, Tennessee, ORNL-NSF-EP-44 (April 1973). 2. W. E. Mooz, The Efecf of Fuel Price Increases on Energy Intensiveness of Freight Transport, Rand Corporation, Santa Monica, California, R&s-NSF (Dec. 1971). 3. A. Sebald and R. A. Herendeen, The Dollar, Energy and Employment Impacts of Air, Rail and Automobile Passenger Transportation, Center for Advanced Computation, University of Illinois, Urbana, Illinois, CAC Document % (Sept. 1974).Reprinted in The Energy Conservation Papers (Edited by Robert H. Wiiiams), Chap. 3. Ballinger, Cambridge, Mass. (1975). 4. B. Hannon and F. Puleo, Transfeting from Urban Cars to Buses: The Energy and Employment Impacts, Center for Advanced Computation, University of Ilhnois, Urbana, Illinois, CAC Document 98 (April 1974). Reprinted in The Energy Conseroation Papers, (Edited by Robert H. Williams), Chap. 3. Ballinger, Cambridge, Mass. (1975). 5. A. C. Masey and R. L. Paullin, Transportation Vehicle Energy Infensities (A Joinr DOT/NASA Reference Paper), NASA Ames Research Center and DOT, Moffett Field, California (20 June 1974). 6. D. B. Shot&a, Transpotiation Enegy Consetxation Data Book: 2nd Edition. Oak Ridge National Laboratories, oak Ridge, Tennessee, ORNL-5320(Oct. 1977). 7. Colloquium of Energy and Patterns of Human Settlement, 2 March 1977, Center for Urban and Regional Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514. 8. A. K. Meier, Tech. Rev. 79, 3 (1977). 9. Energy and the Automobile, Socitey of Automative Engineers, New York, SP-383 (July 1973). IO. M. J. Bernard, Enuironmenral Aspects of a Large Transit Operation, Regional Transit Authority, Chicago, Illinois, TRJS-01 (Nov. 1975). II. Urban Transportation and Energy: The Potenbal Sauings of Different Modes, Congressional Budget Office, Serial No. 95-8 (Sept. 1977). 12. R. A. Herendeen, An Energy Input-Output Matrix for the United States, l%3: User’s Guide, Center for Advanced Computation, University of Illinois, Urbana, IL 61801,CAC Document 69 (March 1973). 13. C. W. Bullard, III and R. Herendeen, Energy Cost of Consumer Goods 1%3/67, Center for Advanced Computation, University of Illinois, Urbana, Illinois, CAC Document I40 (Nov. 1974).Reprinted in Energy Policy, Dec. 1975. 14. Survey of Current Business, U.S. Department of Commerce, July issue. various years. IS. PATH Corp., letter to Environmental Defense Fund, 5 Feb. 1974. 16. PATH Corp., Annual Report. year ending 31 Dec. 1971. 17. PATH Corp. Reply to Motion of Intervenor, ICC. 1 t S No. 8875. I7 Oct. 1973,with 3 attachments. 18. PATH Corp., letter to the author, 23 Jan. 1975.