Tank car and train thereof and loading and unloading systems

A railway train including a plurality of interconnected tank cars, each car comprising a tank with a lading conduit extending the length thereof and having first and second pipes communicating with the interior of the tank with one of the pipes extending to the bottom of the tank and the other terminating adjacent to the top of the tank, the lading conduits of adjacent cars being interconnected by flexible connecting conduits; valve mechanism in the lading conduits and the first and second pipes for closing the lading conduit between the first and second pipes and opening the first and second pipes during loading of fluid lading into the tank and during unloading of fluid lading from the tank and for closing the first and second pipes during transporting of the tank; also disclosed is a loading system and an unloading system for a train of such tank cars.

PRIOR ART STATEMENT AND BACKGROUND OF THE INVENTION 
The present invention relates to railway tank cars, and particularly such 
tank cars adapted for interconnection to accommodate loading and unloading 
of a train of interconnected cars without movement thereof, structure 
being provided for singly and sequentially loading the tank cars with 
fluid lading and singly and sequentially unloading the tank cars of fluid 
lading, and loading and unloading systems for a train of such tank cars. 
The concept of providing fluid communication among a series of 
interconnected railway tank cars is disclosed in the prior art, but 
previous systems have failed to provide a valve mechanism and control 
system therefor useful during loading and unloading of fluid ladings that 
would safely handle certain types of fluid ladings such as compressed 
liquified gases, and particularly liquified petroleum gases. For example, 
prior U.S. Pat. No. 3,897,807 granted Aug. 5, 1975 to D. Hurst and myself 
discloses a unit train of tank cars with the tanks thereof connected in 
series, and also discloses in FIGS. 16 to 19A thereof a train of tank cars 
wherein the individual tanks are connected by input-output conduits 320 
and bypass pipe sections 330 with control valves 335 therein, whereby the 
individual tanks in the unit train can be filled either serially, i.e., 
one after the other with fluid ladings flowing sequentially through each 
of the tanks, or alternatively, the tanks can be loaded in parallel thus 
permitting substantially simultaneous loading of the tanks. When handling 
certain fluid ladings, such as liquified petroleum gases, such loading and 
unloading procedures are not practicable and present safety hazards. 
U.S. Pat. No. 1,542,116 granted June 16, 1925 to R. Welcker discloses 
railway tank cars for interconnection in a manifolded arrangement to 
accommodate continuous emptying of the interconnected tanks from a single 
location, without moving or disconnecting the cars. However, the 
arrangement of the Welcker patent does not provide for continuous loading 
of the interconnected tanks from a single location in a sequential manner, 
and the inter-tank lading connections are along the longitudinal axes of 
the tanks which is found to be a disadvantageous arrangement. 
U.S. Pat. No. 3,675,670 granted July 11, 1972 to O. Ogawa shows railway 
tank cars for interconnection in a manifolded arrangement to accommodate 
continuous loading and unloading of the interconnected tanks from a single 
location. However, the tank cars of the Ogawa patent are not suitable for 
handling of liquified petroleum gases, and the like, and would present 
hazards in the loading operation and the unloading operation and also 
during transportation of the loaded tank cars. 
U.S. Pat. No. 3,722,556 granted Mar. 27, 1973 to W. Jeffers and J. M. 
Jeffers discloses a manifolded tank arrangement which accommodates both 
loading and unloading of a string of interconnected tank cars from a 
single location, but provides the inter-tank lading connections at the 
bottom of the tanks, and provides exposed and unprotected lading flow 
control valves whereby to present a substantial safety hazard during 
transport of the tank cars. 
While the tank car, the loading system and the unloading system of the 
present invention can be utilized with various liquid ladings or 
commodities, the tank car and the loading and unloading systems are 
primarily intended for use in the transportation of liquified compressed 
gases, and specifically liquified petroleum gases, wherein safety is of 
paramount importance. The present invention provides a system wherein in 
the normal loading operation of a string or train of tank cars, only a 
single tank car will be in liquid communication with the lading conduit or 
loading line at any one time; likewise, in the normal unloading operation 
of a string of tank cars, only a single tank car will be in liquid 
communication with the lading conduit or unloading line at any one time. 
More specifically during the loading operation, the gas or vapors that 
remain in the as yet unloaded tank cars are pushed through the tank cars 
serially while the liquid lading is loaded into the tank cars singly and 
in sequence, and actually in parallel one with the other but singly. In 
the unloading of a train of the tank cars, the compressed gas used to 
unload the tank cars is pushed through the tank cars in series so as to 
provide for maximum ventilation thereof, while the liquid lading is 
removed from the tank cars singly and sequentially and therefore in 
parallel but singly. This arrangement provides safety in the case of 
rupture of one of the conduits during the loading or unloading since but a 
single car is exposed at any one time to the dangerous liquid lading. 
There also is a minimum pressure drop in the system during the loading and 
unloading operations since only a single tank car is loaded or unloaded at 
any one time. All this is accomplished while providing a system that is 
compatible with the present transportation systems for such liquified 
compressed gases. 
The prior art on the other hand provides systems wherein there is a 
significant pressure drop along the loading and unloading conduits since 
the tank cars are essentially connected in series during both the loading 
and unloading operations. Rupture in the loading line or the unloading 
line of the prior art structures provides a more serious safety hazard 
when all the tank cars are serially connected since there is no reservoir 
to receive lading in the event of rupture of one of the conduits. 
The arrangement of the present invention provides a safer system in that a 
minimal number of controls are required for the system, and a minimum 
number of openings are required into each tank car. In the prior art on 
the other hand, there were in general more openings required and more 
controls required, whereby more protective structure must be provided 
therefor. 
As will appear more fully hereinafter, the electrical-pneumatic control 
system for the present invention includes a pneumatic accumulator which 
provides a fail-safe reservoir for operating the various control valves to 
close off the tank cars and the lading conduits in the event of the 
breaking of any of the pneumatic lines. The accumulator is incorporated in 
the system so as automatically to close the valves in the lading conduit 
upon completion of the loading of the tank cars and to close the valves 
for the pipes leading into the tank cars upon completion of the unloading 
of the tank cars. 
An additional safety feature resides in the provision of a system wherein 
the failure of any electronic component in a single tank car will not 
disrupt the loading procedure but enables continued loading of the next 
and subsequent tank cars in a train of the tank cars. More specifically, 
upon the failure of an electronic component of the second car in a string 
of tank cars so that the second tank car is not in readiness for loading 
or in the event of failure of any of the valving in the second tank car 
which would prevent loading thereof, the lading conduit across the second 
tank car is still open and loading can proceed with the third tank car or 
any subsequent tank car which is in condition for loading. Each of the 
control valves on the tank cars includes a position indicator so that the 
operator can immediately detect that one of the tank cars is not operating 
properly and can take steps thereafter to repair or remedy the malfunction 
on the second tank car, for example, while loading proceeds with 
subsequent tank cars. As soon as the second tank car is repaired and 
placed in operative condition again, loading of that tank car can proceed 
without interruption of the loading operation. 
SUMMARY OF THE INVENTION 
The present invention provides a railway tank car for unit train service 
which permits a train of such cars to be loaded or unloaded without 
movement thereof from a single location, and accommodates sequential 
loading and unloading of fluid ladings, all with safety and with improved 
economy of time and manpower. 
This is accomplished in the present invention, and it is an object of the 
present invention to accomplish these desired results by providing a 
railway tank car of the character described which includes a tank for 
holding fluid ladings, a wheeled chassis structure mounting the tank with 
chassis coupling means for coupling to the chassis of associated cars, a 
lading conduit on the tank extending substantially the length thereof and 
having coupling means at the ends thereof for coupling to associated 
flexible connecting conduits to place the lading conduit in fluid 
communication with the lading conduits of adjacent like cars, a first pipe 
in communication with the lading conduit extending into the tank and 
terminating at an open end adjacent to the bottom of the tank, a second 
pipe in communication with the lading conduit at a point spaced from the 
first pipe and extending into the tank, and valve mechanism in the lading 
conduit and the first and second pipes for closing the lading conduit 
between the first and second pipes and opening the first and second pipes 
to accommodate loading of fluid lading into the tank and to accommodate 
unloading of fluid lading from the tank and for closing the first and 
second pipes for transporting of the tank. 
Another object of the invention is to provide a railway tank car of the 
type set forth wherein the valve mechanism includes a first control valve 
for selectively opening and closing the lading conduit, a second control 
valve for selectively opening and closing the first pipe, a third control 
valve for selectively opening and closing the second pipe, and valve 
control mechanism operatively connected to the control valves for closing 
the first control valve and opening the second and third control valves to 
accommodate loading of fluid lading into the tank and to accommodate 
unloading of fluid lading from the tank and for closing the first and 
second and third control valves for transporting of the tank. 
Yet another object of the invention is to provide a railway tank car of the 
type set forth wherein the valve mechanism includes a first control valve 
for opening and closing the lading conduit and the first pipe, a second 
control valve for opening and closing the lading conduit and the second 
pipe, and valve control mechanism operatively connected to the control 
valves for actuating the control valves to close the lading conduit 
between the first and second pipes and to open the first and second pipes 
to accommodate loading of fluid lading into the tank and to accommodate 
unloading of fluid lading from the tank and for closing the first and 
second pipes for transporting of the tanks. 
Still another object of the invention is to provide a railway tank car 
train made up of interconnected railway tank cars of the type set forth, 
wherein the individual tanks are singly and sequentially loaded with fluid 
ladings and are singly and sequentially unloaded of fluid lading through 
the free end of the lading conduit on the tank car on one end of the 
train. 
Yet another object of the invention is to provide a railway tank car and a 
train of such tank cars which is particularly adapted and arranged for the 
handling of liquified gases, particularly liquified petroleum gases, with 
safety during the loading and unloading and transportation thereof. 
A further object of the invention is to provide a loading system for 
railway tank car trains of the type set forth for singly and sequentially 
loading the tank cars with fluid lading. 
A still further object of the invention is to provide an unloading system 
for railway tank car trains of the type set forth for singly and 
sequentially unloading the tank cars of fluid lading. 
Further features of the invention pertain to the particular arrangement of 
the parts of the railway tank cars and the trains made up of such tank 
cars, whereby the above outlined and additional operating features thereof 
are attained. 
The invention, both as to its organization and method of operation, 
together with further features and advantages thereof will best be 
understood with reference to the following specification taken in 
connection with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
There is illustrated in FIG. 1 of the drawings a loading system generally 
designated by the numeral 400 for loading fluid ladings, such as 
compressed liquified gases, into a string of three tank cars generally 
designated by the numerals 100A, 100B and 100C. An unloading system 
generally designated by the numeral 500 is illustrated in FIG. 2 of the 
drawings for unloading the string of three tank cars illustrated. The 
specific construction and operation of the loading system 400 and the 
unloading system 500 will be discussed hereinafter. 
There is illustrated in FIGS. 3 and 4 one of the railway tank cars 
generally designated by the numeral 100 made in accordance with and 
embodying the principles of the present invention. A complete tank car 100 
and a portion of a second tank car 100 are illustrated connected to form a 
railway train 50 adapted to be supported by a standard railway track 55. 
The tank car 100 includes a pair of trucks 101 that provide wheeled 
chassis structure and include rail wheels 102 engaging on the railway 
track 55. Couplers 103 are provided at each end of the tank car 100 for 
connection to like tank cars 100 to form the railway train 50. The trucks 
101 support arcuate saddle bolsters 105 that directly support a 
cylindrical elongated tank 110, the draft forces between the trucks 101 
being transmitted through the tank 110. 
The tank 110 is essentially circular in cross section and includes a 
cylindrical shell 111 provided with a sump 112 near the middle thereof and 
at the bottom thereof (see FIG. 7) for a purpose to be described more 
fully hereinafter. The ends of the shell 111 are closed by dome-shaped 
tank heads 115 to provide a fully enclosed tank 110. Mounted on the tank 
110 at the upper portion thereof are catwalks designated by the numeral 
116 and railings designated by the numeral 117. 
Referring particularly to FIG. 4, a lading conduit 120 is provided that 
extends essentially the length of the tank 110 on the top thereof, the 
central portion of the lading conduit 120 having an offset section 121 
connected thereto by connecting sections 122. Each end of the lading 
conduit 120 carries a coupling member 125, the ends of the lading conduit 
120 terminating inboard of the ends of the associated tank 110. In order 
to interconnect the lading conduits 120 of adjacent railway tank cars in 
the train 50, flexible connecting conduits 130 are provoided. It will be 
understood that other "flexible" connections may be used in place of the 
connecting conduits 130, other conduit interconnecting means being 
acceptable so long as they accommodate all of the relative movements 
between two coupled tank cars in train action. Each of the conduits 130 
has coupling means 131 on each end thereof engaging with the coupling 
means 125. When not in use, the connecting conduit 130 is stored in a 
mount 132 provided on the tank 110 adjacent to one end thereof. In order 
to maintain the flexible connecting conduit at the proper position, a 
support arm 135 therefor is provided which is mounted upon one end of the 
tank 110 at a pivot 136 and extends outwardly therefrom towards the 
adjacent tank 110 and carries on the outer end a clamp 137 engaging the 
associated connecting conduit 130 so as to hold the connecting conduit 130 
in the proper position at all times during transport of the railway tank 
cars 100. 
Mounted centrally of each of the tanks 110 and on top thereof is a 
protective housing 140 into which extends the offset section 121 of the 
lading conduit 120 and within which are housed a first preferred 
embodiment of the control valves and valve control mechanism of the 
present invention. Referring particularly to FIGS. 5 and 6 of the 
drawings, it will be seen that the protective housing 140 includes a pair 
of opposed end walls 141 having openings 142 therein receiving the offset 
section 121 of the lading conduit 120. Opposed side walls 143 are provided 
integrally joined at the ends with the end walls 141 and in turn all of 
the walls 141 and 143 are joined to a bottom wall 145, such as by welding. 
The bottom wall 145 has an opening 146 centrally therein and is secured 
for mounting purposes upon a mounting plate 147 that is securely fastened 
to the shell 111 of the tank 110. 
The righthand conduit section 121 as viewed in FIGS. 5 and 6 is connected 
to a first pipe 150 that extends vertically through the mounting plate 147 
and the shell 111 and into the interior of the tank 110 and terminates 
essentially in the associated sump 112 (see FIG. 7). More specifically, 
the conduit section 121 is connected by a coupling 151 to a pipe section 
152 that in turn is connected to a tee 153. The leg of the tee 153 carries 
a pipe section 154 that connects with an elbow 156 that in turn connects 
with a pipe section 157 and a second elbow 158 to a pipe section 159. 
Disposed between the pipe section 159 and the first pipe 150 is a control 
valve generally designated by the numeral 160. The control valve 160 is 
provided with an actuator 161 which is pneumatically driven, and is 
connected by a coupler 162 to the control valve 160 so as to control the 
position thereof. The position of the control valve 160 is visually 
indicated by a valve position indicator 169 mounted on and driven by the 
actuator 161. Control gas supply for the actuator 161 is in part derived 
from an accumulator tank 165 on which is disposed a spool or pilot valve 
210. Gas for the accumulator tank 165 is received from a main gas line 166 
through a gas line 203, a check valve 204 and a gas line 205. The output 
from the spool valve 210 appears on a first control gas line 214 and a 
second control gas line 215, both of which are connected to the control 
valve actuator 161. The term "gas" as used herein includes any suitable 
control gas such as nitrogen as well as air, and in fact the preferred gas 
is nitrogen as will be explained more fully hereinafter. 
A second pipe 170 extends vertically through the mounting plate 147 and the 
shell 111 of the tank 110 and into the body thereof and terminates in an 
open end a short distance below the top of the tank shell 111, see FIG. 5 
particularly. A coupling 171 connects the lefthand conduit section 121 in 
FIGS. 5 and 6 to a pipe section 172 that is in turn connected to one arm 
of a tee 173, the leg of the tee 173 being connected by a pipe section 174 
to an elbow 176 which in turn carries a pipe section 177 connected by an 
elbow 178 to a pipe section 179. A control valve 180 interconnects and is 
interposed between the pipe section 179 and the second pipe 170. Referring 
to FIG. 5, it will be seen that an actuator 181 is provided for the 
control valve 180, the actuator 181 being of the pneumatic type. A coupler 
182 connects the actuator 181 to the control valve 180, the position of 
the control valve 180 being visually indicated by a valve position 
indicator 189 mounted on and driven by the actuator 181. The control gas 
lines 214 and 215 both also connect with the actuator 181, whereby the 
actuators 161 and 181 are actuated in synchronism under the control of the 
spool valve 210, this serving to control the positions of the control 
valves 160 and 180 substantially at the same time. A vent line 230 extends 
vertically through the mounting plate 147 and into the tank 110 and 
terminates in an open lower end a short distance below the lower end of 
the pipe 170. The upper end of the vent line connects to a manually 
operable valve 235 that is connected by a bypass line 231 to the pipe 
section 172 for a purpose to be described later. 
A control valve 190 is interposed in the lading conduit section 121 between 
the first pipe 150 and the second pipe 170, the control valve 190 being 
provided with an actuator 191 which is pneumatically operated and is 
connected by gas lines (not shown) to a spool or pilot valve 221 (see 
FIGS. 17 and 18). The actuator 191 is connected by a coupler 192 to the 
control valve 190, and the position of the control valve 190 is visually 
indicated by a valve position indicator 199. The control valve 190 is 
connected by pipe sections 193 and couplings 194 to the other arm of the 
tees 153 and 173. There also is provided in FIG. 5 a safety valve 185 
which provides an outlet for gases within the tank 110 if the pressure 
therein rises above the predetermined level set by the safety valve 185. 
There further is provided a liquid level sensor 195 which senses the 
unloaded condition of the tank 110, i.e., the lowering of the fluid level 
within the tank 110 to or below the lower open end of the first pipe 150. 
The liquid level sensor 195 also senses either of two loaded conditions of 
the tank 110, the first being a lower or "summer" level loaded condition 
and the second being a higher or "winter" level loaded condition, the 
level of both loaded conditions being below the lower end of the second 
pipe 170 with the "winter" level loaded condition setting being 
immediately below the lower end of the second pipe 170, and the "summer" 
level loaded condition setting being immediately below the lower end of 
the vent line 230, thus to control the outage or free vapor space in the 
filled tank car. 
Referring to FIGS. 17 and 18, there is illustrated the electrical-pneumatic 
control system 200 for controlling the positions of the control valves 
160, 180 and 190, and specifically the associated valve actuators 161, 181 
and 191 therefor, respectively. A solenoid control valve 201 is provided 
including an operating solenoid 202 having input conductors 425, one of 
the input ports of the solenoid control valve 201 being connected to the 
main gas line 166, while one of the outlet ports is connected to a gas 
line 203 and the other two outlet ports are connected to a gas line 206. 
The gas line 203 is connected as one of the inputs to a spool valve 210 
that controls the valve actuators 161 and 181. The spool valve 210 
includes the usual spool 212 and a return spring 213. One of the outlet 
ports of the spool valve 210 is connected to the gas line 214, while the 
other two outlet ports are connected to the gas line 215. As has been 
explained heretofore, the gas line 214 is also connected as one of the 
inputs to the valve actuators 161 and 181 while the gas line 215 is 
connected to one of the inlets to the valve actuators 161 and 181. 
The accumulator 165 is also charged with gas under pressure from the main 
gas line 166 through the solenoid control valve 201 and the gas line 203. 
More specifically, the gas line 203 is connected to a check valve 204 with 
the outlet of the check valve 204 being connected by a gas line 205 to the 
first connection to the accumulator 165. A second connection to the 
accumulator 165 is made by a gas line 208 which is connected to the gas 
line 206 through the check valve 207. The valve actuator 191 is controlled 
by a spool valve 221 having a spool 222 returned by a spring 223. A 
connection is made from the gas line 206 to the spool valve 221 and one of 
the input ports to the spool valve is connected to the gas line 208. One 
of the outlet ports of the spool valve 221 is connected by a line 225 to 
the valve actuator 191 while the other two outlet ports of the spool valve 
221 are connected by a gas line 224 to the other connection to the valve 
actuator 191. 
When an unloaded tank car 100 is to be loaded with liquified compressed 
gases, the control valves 160, 180 and 190 are initially closed and there 
is no connection to the main gas line 166 and there is no electrical 
connection to the conductors 425 connected to the solenoid control valve 
201. The first step in the loading operation is to connect a supply of gas 
under pressure, preferably an inert gas such as nitrogen, to the main gas 
line 166. The conductors 425 are connected to a terminal control system 
(to be described more fully hereinafter). The solenoid control valve 201 
is initially in the position illustrated in FIG. 17, and accordingly upon 
connection of the gas supply to the main gas line 166 (at 90 p.s.i.g. or 
higher pressure), the line 166 is connected through the solenoid control 
valve 201 to the line 203. The accumulator 165 is charged through the 
check valve 204 and the line 205 to essentially the pressure in the line 
166. The pressure in the line 166 is also conveyed through the line 203 to 
move the spool valve 210 from the spring held position of FIG. 18 to the 
position illustrated in FIG. 17. The pressure from the line 205 is then 
applied through the spool valve 210 to the line 214, this moving the valve 
actuators 161 and 181 to the open positions thereof, thus opening the 
associated valves 160 and 180, respectively, and thus opening the 
associated pipes 150 and 170. It is noted that the line 215 is vented at 
the spool valve 210 which is held in the position illustrated in FIG. 17 
against its spring 213 by the pressure in line 203. The spool valve 221 is 
held in the position illustrated in FIG. 17 by its spring 223, it being 
noted that the spool valve 221 is not pressurized. In fact, pressure is 
supplied from the line 208 through the spool valve 221 to the line 224 
that holds the valve actuator 191 in the closed position thereof and thus 
to hold the valve 190 closed and thus closing the lading conduit 120 
between the pipes 150 and 170. 
Upon the associated fluid level sensor 195 detecting the loaded condition 
of the tank car 100, a signal is sent thereby to a terminal control system 
and the return signal is received on the conductors 425 to shift the 
solenoid control valve 201 in the tank car 100 from the position 
illustrated in FIG. 17 to the position illustrated in FIG. 18 (all as to 
be described more fully hereinafter). The main gas line 166 is now 
connected through the solenoid control valve 201 to the line 206 and the 
line 203 is open to vent and has no pressure applied thereto from the main 
line 166. Since there is no pressure applied to the line 203, the spring 
213 in the spool valve 210 returns the spool 212 to the right as viewed in 
FIG. 18 and this connects the line 205 through the spool valve 210 to the 
line 215 to move the valve actuators 161 and 181 to close the associated 
valves 160 and 180, and thus to close the associated pipes 150 and 170. It 
is noted that the line 214 is open to exhaust to enable the closing of the 
valves 160 and 180. The pressure in the line 208 charges the accumulator 
165 to essentially the same pressure as in the main gas line 166. Since 
the spool 212 of the valve 210 is held in the position illustrated in FIG. 
18 by the spring 213, gas in the accumulator 165 through line 205 enters 
the line 215. Pressure in the line 206 also moves the spool 222 of the 
spool valve 221 to the position illustrated in FIG. 18 and thus connects 
the line 208 through the spool valve 221 to the line 225 which moves the 
valve actuator 191 to the open position thereof, thus opening the 
associated valve 190 and the lading conduit 120 between the associated 
pipes 150 and 170. If the pressure in the line 166 is lost or relieved, 
the line 206 will be depressurized and the spool 222 of the valve 221 will 
be moved by its spring 223 to the position illustrated in FIG. 17. 
Thereupon gas from the accumulator through line 208 enters line 224 to 
move the valve actuator 191 and the associated valve 190 to the closed 
positions thereof, it being noted that the pressure in the line 225 will 
have been relieved. 
There is illustrated in FIG. 1 of the drawings the loading system 400 for 
loading liquified compressed gas into a train 50 of the tank cars 100. A 
supply 401 of liquified compressed gases is provided having an outlet pipe 
402 with a control valve 403 therein and connected to a pump 405 and 
particularly the suction inlet thereof by a pipe 406, the discharge outlet 
of the pump 405 being connected by a pipe 407 to a valve 408 connected to 
the loading conduit 60 that in use is connected to the adjacent end of the 
lading conduit 120 on the adjacent car 100. A supply 410 of compressed gas 
is also provided, the preferred gas being nitrogen, under a pressure of at 
least 90 p.s.i.g. Other gases, including air, can be used, but inert gases 
such as nitrogen are preferred to reduce the explosion hazards during the 
loading operation. The nitrogen supply 410 has its outlet connected to an 
outlet pipe 411 in which is disposed a first valve 412 that connects to 
the loading conduit 60, and a second control valve 413 that connects to 
the adjacent end of the main gas line 165 on the adjacent tank car 100. 
There further is provided a vapor recovery system 415 having the inlet 
thereof connected to the conduit 65 connecting with the last tank car 100C 
in the train 50, and connecting specifically to the adjacent end of the 
lading conduit 120, the outlet of the vapor recovery system 415 being 
connected by a pipe 416 to the inlet of the supply 401. Finally, there is 
provided a terminal control system 420 having an electrical power supply 
generally designated by the numeral 421 provided on conductors 422 and 
423. One output from the terminal control system 420 is the conductor 425 
that connects to each of the solenoid control valves 201 described 
hereinabove. There also is provided a conductor 426 connected to each of 
the fluid or liquid level sensors 190. 
Referring to FIGS. 1, 7-10, 17 and 18, a typical loading cycle using the 
loading system 400 will be described in detail. There has been provided a 
railway siding 55 adjacent to the supply 401 of liquified compressed gas, 
and disposed upon the railway siding 55 is a string of tank cars 100, 
three having been shown for purposes of illustration only. It is intended 
that strings of tank cars 100, for example, ten cars in length will be 
provided, and it is further contemplated that several of the groups of ten 
tank cars may be connected in a single train to provide a unit train of 
tank cars. In order to distinguish among the cars in the train 50 in FIGS. 
1 and 7-10, the reference numerals applied to the railway tank cars 100 of 
FIGS. 2-6 have had suffixes "A", "B" and "C" applied from right to left in 
FIGS. 1 and 7-10. The tank cars 100A to 100C arrive in position on the 
rails 55 in an unloaded condition and the free end of the lading conduit 
120A disposed to the right has a cap thereon closing that the end of the 
lading conduit 120A and the lefthand end of the lading conduit 120C also 
has a cap thereon. The cap on the righthand end of the lading conduit 120A 
is removed and the loading conduit 60 is coupled thereto, and the cap on 
the lefthand end of the lading conduit 120C is removed and a vapor line or 
conduit 65 is attached thereto. It will be appreciated that although the 
tank cars 100A to 100C are unloaded, there still remains therein a 
quantity of liquified compressed gas, or at least the vapors thereof, 
which may typically have a pressure on the order of 100 p.s.i.g., whereby 
upon opening of the valves associated therewith, an immediate pressure on 
the order of 100 p.s.i.g. is provided at the ends of the conduits 60 and 
65. The conduit 60 is connected to the outlet of the valve 408 for the 
pump 405 while the conduit 65 is connected to the input to the vapor 
recovery system 415. Accordingly, the entire system will immediately be 
under pressure on the order of 100 p.s.i.g. and there will be a minimal 
introduction of air or oxygen into the system, thus minimizing the 
likelihood of a fire or explosion. The nitrogen supply 410 is connected 
through the valve 413 to the main gas line 166 and pressure is applied 
thereto on the order of 90 p.s.i.g. Finally, the conductor 425 is 
connected to the solenoid control valves 201 and the conductor 426 from 
the terminal control system 420 is connected to the liquid level sensors 
195. 
When the tank cars 100A to 100C arrive for the loading operation, all of 
the control valves 160, 180 and 190 are closed. Furthermore, the solenoid 
control valves 201 and the spool valves 221 are in the positions 
illustrated in FIG. 17 of the drawings, while the spool valve 210 is in 
the position illustrated in FIG. 18. When the nitrogen supply 410 is 
connected to the main gas line 166 and the valve 413 opened, the high 
pressure gas will be directed by the solenoid control valves 201 to the 
lines 203 which will immediately begin charging the accumulators 165 and 
will move the spools 212 against the springs 213 in the spool valves 210 
so as to connect the lines 205 to the lines 214. This will cause the valve 
actuators 161 and 181 to move so as to open the associated control valves 
160 and 180 on all of the cars in the train 50, the lines 215 being vented 
to the atmosphere through the spool valves 210. It is noted that the 
control valves 190 will remain closed since no pressure will be applied 
along the line 206 to the spool valve 221 and pressure will be applied 
from the accumulator 165 through the line 208, the spool valve 221 and the 
line 224 to hold the actuators 191 and the associated valves 190 in the 
closed positions thereof. 
Fluid lading, such as liquified petroleum gas, is now pumped from the 
supply 401 through the outlet pipe 402, the open valve 403, the pipe 406 
via the pump 405 and then through the pipe 407 and the open valve 408 to 
the loading conduit 60 and then into the lading conduit 120A. The fluid 
lading flows through the open valve 160A and down through the first pipe 
150A and into the interior of the tank car 100A. The valve 190A is closed 
while the valve 180A is open, whereby the fluid lading flows only through 
the first pipe 150A. Referring to FIG. 7, the tank car 100A is shown 
partially filled as at a fluid level 70A therein. The vapors generated 
during the loading operation of the tank car 100A pass upwardly through 
the second pipe 170A, and specifically through a vapor nozzle at the open 
end thereof and into that portion of the lading conduit 120A disposed to 
the left of the control valve 190A and into the next tank car 100B, for 
venting and pressure equalization of vapors that might be therein. Since 
the valves 160 and 180 in the tank cars to the left of the tank car 100A 
are all open and the valves 190 on the tank cars to the left of the tank 
car 100A are all closed, the vapors will pass from car to car and will 
exit through the vapor conduit 65 and thus to the input to the vapor 
recovery system. The recovered liquified compressed gas from the vapor 
recovery system 415 are conveyed by the pipe 416 to the input of the 
supply 401 of liquified compressed gas. 
When the fluid level in the tank 110A reaches a predetermined point 
illustrated by the numeral 71A in FIG. 8, the liquid level sensor 195A is 
activated and generates a control signal that is conveyed by the conductor 
426 to the terminal control system 420. The terminal control system 420 in 
turn creates a control signal that is conveyed by the conductors 425 and 
is applied to the solenoid control valve 201 on the car 100A to move the 
parts thereof to the positions illustrated in FIG. 18. The main gas line 
166 is now connected to the line 206 and through the check valve 207 to 
the line 208 whereby further to charge the accumulator 165 and to move the 
spool 222 on the spool valve 221 to the position illustrated in FIG. 18. 
Gas pressure is now applied through the spool valve 221 from the line 208 
to the line 225 which moves the valve actuator 191 to a position to open 
the associated control valve 190 and thus to open the lading conduit 120A. 
In the meantime, pressure has been relieved from the spool valve 210 and 
therefore the spring 213 moves the spool 212 to the position illustrated 
in FIG. 18 which relieves the pressure from the line 214. Thereupon gas 
from the accumulator through line 205 enters line 215 and serves to move 
the valve actuators 161 and 181 to positions to close the associated 
valves 160A and 180A, respectively, and thus to close the pipes 150A and 
170A. The tank car 100A is now loaded and the loading position shifts to 
the car 100B since the valves 160B and 180B are open therein while the 
valve 190B is closed. 
The liquified compressed gas now flows from the supply 401 under the urging 
of the pump 405 and through the opened valves 403 and 408 into the loading 
conduit 60 and through the lading conduit 120A and connecting conduit 130 
and into the righthand portion of the lading conduit 120B. Since the valve 
190B is closed, the lading is diverted and flows through the pipe 150B. 
The tank car 100B is then loaded in the same manner as was tank car 100A 
described above. When the tank car 100B is fully loaded, the liquid level 
sensor 195B senses the fully loaded condition and sends a signal by the 
conductor 426 to the terminal control system 420 which in turn generates a 
control signal that is conveyed along the conductors 425 to the solenoid 
control valve 201 associated with the tank car 100B. Actuation of the 
solenoid control valve 201 on the tank car 100B serves to open the control 
valve 190B to open the lading conduit 120B and to close the control valve 
160B and 180B and to close the associated pipes 150B and 170B as 
correspondingly previously described in connection with tank car 100A. 
With the control valves 190A and 190B open and the control valves 160A and 
180A closed and the control valves 160B and 180B closed, a passage is now 
completed from the pump 405 through the valve 408 and the loading conduit 
60 through the lading conduits 120A and 120B and the associated connecting 
conduits 130 to the righthand end of the lading conduit 120C. The control 
valves 160C and 180C are open while the control valve 190C is closed. 
Accordingly, the fluid lading is loaded into the tank car 100C through the 
first pipe 150C. Loading of the tank car 100C proceeds as described above 
with respect to the loading of the tank cars 100A and 100B until the 
liquid level sensor 195C senses the loaded condition of the tank car 100C 
as illustrated in FIG. 10. At this time, the liquid level sensor 195C will 
produce a signal conveyed by the conductor 426 to the terminal control 
system 420 which in turn will generate a control signal conveyed by the 
conductors 425 to the solenoid control valve 201 on the tank car 100C. 
This will shift the solenoid control valve 201 on the tank car 100C from 
the position illustrated in FIG. 17 to that illustrated in FIG. 18 This 
will serve to open the control valve 190C and to close the control valves 
160C and 180C. The string of cars at the loading system 400 is now 
completely loaded. 
It will be understood that during the entire sequence of loading of the 
tank cars 100A, 100B and 100C, the vapors generated are passed from car to 
car and outwardly eventually through the vapor conduit 65 to the inlet to 
the vapor recovery system 415, and the recovered vapors are then conveyed 
by the pipe 416 to the inlet of the supply 401 of liquified compressed 
gases. With the loading of the various tank cars now essentially completed 
as illustrated in FIG. 10, the lading conduits 120A, 120B and 120C are 
then purged of liquid and commodity vapor. This is accomplished by closing 
the valve 408 and opening the valve 412, thus to supply nitrogen gas from 
the supply 410 thereof through the outlet pipe 411, the now open valve 412 
and the loading conduit 60 and through the lading conduits 120A, 120B and 
120C outwardly through the conduit 65 to the inlet to the vapor recovery 
system 415. It will be understood that all of the valves 160 and 180 are 
closed at this time and all of the valves 190 are open, the solenoid 
control valves 201 being in the positions illustrated in FIG. 18. After 
the purging, the valve 412 is closed and the loading conduit 60 is 
disconnected from the righthand end of the lading conduit 120A and a cap 
is placed thereon. Likewise, the conduit 65 is removed from the lefthand 
end of the lading conduit 120C and a cap placed on the free end of the 
lading conduit 120C. The connection between the valve 413 and the main gas 
line 166 is removed and the conductors 425 and 426 are disconnected from 
the adjacent car 100A. Disconnection of the gas supply from the main gas 
line 166 removes the pressure from the line 206 (see FIG. 18) and thereby 
removes the pressure from the spool valve 221 permitting the spring 223 
thereof to move the parts to the position illustrated in FIG. 17. As a 
consequence, the line 208 is connected through the spool valve 221 to the 
line 224 and the pressure within the accumulator 165 serves to move the 
valve actuator 191 to close the associated valve 190. In this manner, all 
of the valves 190A, 190B and 190C in the train 50 are moved to the closed 
positions thereof. Summarizing, all of the valves 160, 180 and 190 along 
the entire length of the train 50 are now in the closed positions. These 
valves all remain in the closed positions during the transport of the 
train 50 to the point of unloading. 
There is illustrated in FIG. 2 of the drawings the unloading system 500 for 
unloading liquified compressed gas from a train 50 of the tank cars 100. A 
container 501 for liquified compressed gas is provided having an inlet 
connection 502 with a control valve 505 therein connecting to an unloading 
conduit 80 that in use is connected to the adjacent end of the lading 
conduit 120 on the adjacent car 100. A supply 510 of compressed gas is 
also provided, the preferred gas being nitrogen, under a pressure of at 
least 90 p.s.i.g. The nitrogen supply 510 has an outlet connection 511 in 
which is disposed a valve 513 that connects to the adjacent end of the 
main gas line 166. Compressed gas vapors from the container 501 of 
liquified compressed gas are used as the motive power for unloading the 
tank cars 100A, 100B and 100C. To that end there has been provided a 
compressor 515 having its suction side connected by a line 516 through a 
valve 518 to the container 501 to withdraw vapors therefrom, and having 
its discharge side connected to a discharge line 517 that is connected 
through a valve 519 to the conduit 85. Finally, there is provided a 
terminal control system 520 having an electrical power supply generally 
designated by the numeral 521 provided on two conductors 522 and 523. One 
output from the terminal control system 520 is the conductor 525 that 
connects to each of the solenoid control valves 201 described hereinabove. 
There also is provided a conductor 526 connected to each of the fluid or 
liquid level sensors 190. 
Referring to FIGS. 2, 11-14, 17 and 18, a typical unloading cycle using the 
unloading system 500 will be described in detail. There has been provided 
a railway siding including tracks 55 adjacent to the container 501 for 
liquified compressed gases, and the train to be unloaded is positioned 
thereon. 
The solenoid control valves 201 are in the positions illustrated in FIG. 
18, and since no pressure is applied to the line 166, all of the valves 
160, 180 and 190 are closed and are further urged into the closed 
positions by the air pressure provided from the accumulator 165 through 
the line 215 for the control valves 160 and 180 and through the line 224 
for the control valve 190. The unloading conduit 80 is connected to the 
righthand end of the lading conduit 120A and is connected through the 
valve 505 and the line 502 to the inlet for the container 501 for 
liquified compressed gas. The conductor 525 from the terminal control 
system 520 is connected to the conductors for the solenoid control valves 
201, and the conductor 526 is connected to the liquid level sensors 195. 
The supply 510 of nitrogen under pressure is connected by the pipe 511 
through the valve 513 to the main gas line 166. Finally, the valve 519 is 
connected to the unloading conduit 85 attached to the lefthand end of the 
lading conduit 120C. Upon opening of the valve 513, pressure will be 
applied to the line 166 and as is best illustrated in FIG. 18 of the 
drawings, pressure is then applied through the solenoid control valves 201 
to the lines 206 which actuate the spool valves 221 to the position 
illustrated in FIG. 18 and also supplies pressure to the line 208 so as to 
deliver pressure through the spool valves 221 to the lines 225 that moves 
the valve actuators 191 to open the associated control valves 190, thus to 
open the associated lading conduits 120, the lines being vented to 
atmosphere through the spool valves 221. In other words, application of 
pressure to the line 166 serves to open all of the control valves 190A, 
190B and 190C, thus to provide a single open conduit from the unloading 
conduit 80. The pressurized lines 208 also charge the accumulator 165 and 
the lines 205 which through the spool valves 210 pressurizes the lines 215 
to hold the valve actuators 161 and 181 and the associated valves 160 and 
180 closed. Opening of the valves 518 and 519 now applies the commodity 
gas vapors under pressure from the compressor 515 to the lefthand end of 
the lading conduit 120C. At this time the operator causes a control signal 
to be generated at the terminal control system 520 and conveyed along the 
conductor 525 to the solenoid control valve 201 on the tank car 100C. This 
control signal shifts the solenoid control valve 201 on tank car 100C from 
the position illustrated in FIG. 18 to that illustrated in FIG. 17. As a 
consequence, the control valves 160C and 180C are opened, thus to open the 
associated pipes 150C and 170C, while the control valve 190C is closed, 
thus to close the lading conduit 120C between the pipes 150C and 170C. The 
fluid lading is then forced by the pressure of the gases from the 
compressor 515 out of the tank 110C up through the pipe 150C and into the 
righthand portion of the lading conduit 120C and then through the 
interconnected lading conduits 120B and 120A and the associated connecting 
conduits 130 to the right and to the unloading conduit 80. This action 
will continue until the tank car 100C is unloaded, it being noted that the 
lading therefrom flows directly into the container 501 without entering 
any of the other tank cars in the train 50. 
When the tank car 100C is unloaded, the liquid level sensor 195C is 
activated and generates a control signal that is conveyed by the conductor 
526 to the terminal control system 520. The terminal control system 520 in 
turn creates a control signal that is conveyed by the conductor 525 and is 
applied to the solenoid control valve 201 on the tank car 100B which 
shifts the solenoid control valve 201 on the tank car 100B from the 
position illustrated in FIG. 18 to that illustrated in FIG. 17. As a 
consequence, the control valves 160B and 180B are opened, thus to open the 
associated pipes 150B and 170B, while the control valve 190B is closed, 
thus to close the lading conduit 120B between the pipes 150B and 170B. The 
fluid lading is then forced by the pressure of the compressed gases from 
the compressor 515 out of the tank 100B up the pipe 150B and into the 
righthand portion of the lading conduit 120B and then through the 
interconnected lading conduit 120A and the associated connecting conduit 
130 to the right and to the unloading conduit 80. This action will 
continue until the tank car 100B is unloaded, it being noted that the 
lading therefrom flows directly into the container 501 without entering 
any of the other tank cars in the train 50. 
When the tank car 100B is unloaded, the liquid level sensor 195B is 
activated and generates a control signal that is conveyed by the conductor 
526 to the terminal control system 520. The terminal control system 520 in 
turn creates a control signal that is conveyed by the conductors 525 and 
applied to the solenoid control valve 201 on the car 100A to move the 
parts thereof from the positions illustrated in FIG. 18 to the positions 
illustrated in FIG. 17. As a consequence, the control valves 160A and 180A 
are opened, thus to open the associated pipes 150A and 170A, while the 
control valve 190A is closed, thus to close the lading conduit 120A 
between the pipes 150A and 170A. The fluid lading is then forced by the 
pressure of the compressed gases from the compressor 515 out of the tank 
110A up through the pipe 150A and into the righthand portion of the lading 
conduit 120A and then to the unloading conduit 80. This action will 
continue until the tank car 100A is unloaded, it being noted that the 
lading therefrom flows directly into the container 501 without entering 
any of the other tank cars from the train 50. 
With all of the tank cars 100A, 100B and 100C now unloaded, it will be 
noted that the valves 190A, 190B and 190C are all closed while the valves 
160A, 160B, 160C, 180A, 180B, and 180C are all open. Disconnection of the 
valve 519 from the unloading conduit 85 and disconnection of the nitrogen 
supply 510 from the main gas line 166 leaves the control solenoids 201 in 
the position illustrated in FIG. 17 and removes pressure from the lines 
203, whereby the spool valves 210 are returned by the springs 213 to the 
position illustrated in FIG. 18. The pressure in the accumulators 165 
applied through the lines 205 to the lines 215 move the valve actuators 
161 and 181 and the associated control valves 160 and 180 all to the 
closed positions. It will be seen therefore that all of the control valves 
160, 180 and 190 are now in the closed positions, and these valves all 
remain in the closed positions during the transport of the unloaded train 
50 to the point of loading. 
From the above description of the loading system of FIG. 1 and the 
unloading system of FIG. 2, it will be seen that the train 50 can be fully 
loaded and fully unloaded from a single location without any movement 
thereof and without any movement of the tank cars 100 within the train 50 
and without disconnecting any of the tank cars 100 one from another. The 
loading of the tank cars 100 is accomplished singly and in sequence from 
right to left as viewed in FIGS. 1 and 7-10, the interconnected lading 
conduits 120 with the associated connecting conduits 130 forming a common 
header or manifold. Only a single tank car 100 will be in liquid 
communication with the lading conduit 120 at any one time, and when 
unloading only a single tank car 100 will be in liquid communication with 
the lading conduit 120 at any one time. The gas or vapors are pushed 
through the tank cars serially during both loading and unloading, yet the 
liquid is loaded into the tank cars singly and sequentially and 
essentially in parallel, while in unloading the tank cars 100 are also 
unloaded singly and sequentially. Only one tank car 100 has the tank 110 
thereof holding the liquid commodity exposed to the lading conduit 120 at 
one time during both loading and unloading. 
Since the liquid lading is loaded singly and sequentially into the cars and 
is unloaded singly and sequentially therefrom, the system of the present 
invention does not have the cumulative pressure drops associated with 
prior systems wherein the liquid lading is loaded in series and is 
unloaded in series through the several tank cars. 
The accumulators 165 provide a fail-safe reservoir in the event of the 
breaking of any of the main supply lines such as 166, or the lines 203 and 
206. The accumulator serves to close the valves 190 upon the completion of 
the loading of the tank cars 100 and to close the control valves 160 and 
180 upon the completion of the unloading of the tank cars 100. 
An additional safety feature results from the utilization of a system 
wherein the failure of the electronic components in a single tank car 100 
will not disrupt the entire loading procedure, but will enable continued 
loading of the tank cars. More specifically, upon the failure of an 
electronic component on the tank car 100B, for example, so that the tank 
car 100B is not in readiness for loading, or in the event of failure of 
any of the valving in the tank car 100B which would prevent loading 
thereof, the lading conduit 120B across the tank car 100B is still open 
and loading can proceed with the tank car 100C or any subsequent tank car 
which is in condition for loading. Each of the control valves 160, 180 and 
190 on the tank cars 100 includes a position indicator 169, 189 and 199, 
respectively, so that the operator can immediately detect that one of the 
tank cars 100 is not operating properly and can take steps thereafter to 
repair or remedy the malfunction on the tank car 100B, for example, while 
loading proceeds with subsequent tank cars 100C, etc. As soon as the tank 
car 100B is repaired and placed in operative condition again, loading of 
the tank car 100B can proceed without interruption of the loading 
operation. 
During the summertime the "summer" level loaded condition should be 
established by the proper actuation of the liquid level sensor 195A, for 
example, at the lower end of the vent line 230 (see FIG. 6). Failure of 
the liquid level sensor 195A would cause the filling of the tank 100A to 
continue until the "winter" level loaded condition is slightly exceeded, 
i.e., loading to the lower end of the second pipe 170A. Loading of the 
next tank car 100B will proceed since the commodity lading will simply 
flow upwardly through the second pipe 170A and into the lading conduit 
120A and then to the tank car 100B. Such a malfunction of the liquid level 
sensor 195A will be detected by the workmen filling the train of tank cars 
100 since after filling the valve position indicators 169A and 189A on the 
control valves 160A and 180A, respectively, on the tank car 100A will be 
in the open positions thereof rather than in the closed positions thereof 
and the valve position indicator 199A on the control valve 190A will also 
indicate that that valve is in the closed condition thereof and not the 
open condition thereof as it should be when the tank car 100A is filled. 
The operator will upon detecting the failure of the liquid level sensor 
195A by observing the positions of the valve position indicators 169A, 
189A, and 199A manually close the valves 160A and 180 and manually open 
the valves 190A and 235 (see FIG. 6). The liquid level in the car 100A 
will be lowered by the vapor pressure in the car to the bottom of the vent 
line 230, the extra lading being forced by the pressure within the car 
100A upwardly through the vent line 230, through the valve 235 and through 
the bypass line 231 to the pipe section 172 and then to the lading conduit 
120. As soon as the excess commodity lading has been thus removed from the 
tank car 100A, the valve 235 is manually closed by the operator. 
There is illustrated in FIGS. 15, 16, 19 and 20 of the drawings a second 
preferred embodiment of the control valves and valve control mechanisms of 
the present invention, all housed within a protective housing 240. Many of 
the parts illustrated in FIGS. 15, 16, 19 and 20 are identical in 
construction and operation with parts of the control valves and valve 
control mechanism illustrated in FIGS. 5, 6, 17 and 18 of the drawings, 
and accordingly, where appropriate, like reference numerals in the 200 
series have been applied to parts in FIGS. 15, 16, 19 and 20 that 
correspond to like numbered parts in the 100 series in FIGS. 5, 6, 17 and 
18. 
The protective housing 240 in FIGS. 15 and 16 is cylindrical in shape and 
includes a cylindrical side wall 241 having openings 242 therein receiving 
the offset section 221 of an associated lading conduit 220. The lower 
portion of the side wall 241 is joined to a bottom wall 245, such as by 
welding, the bottom wall 245 having an opening 246 centrally therein and 
secured to a mounting plate 247 by a plurality of fasteners 248. The 
mounting plate 247 is firmly secured to the shell 211 of an associated 
tank car. 
The righthand conduit section 221 as viewed in FIGS. 15 and 16 is connected 
to a coupling 251 which is in turn connected to a first control valve 260. 
The control valve 260 has communicating therewith a first pipe 250 that 
extends vertically downwardly through the mounting plate 247 and the shell 
211 and into the interior of the associated tank and terminates in an 
associated sump (not shown) like the sump 112 described above. The control 
valve 260 is provided with an actuator 261 which is pneumatically driven 
and serves to control the valve 260 between a first or normal position 
wherein lading flows through the conduit section 221 from the right to the 
left and through the valve 260 with the pipe 250 blocked, and a second 
load/unload position wherein fluid lading flows from the right along the 
conduit section 221 and into the pipe 250, the conduit section 221 being 
blocked to the left of the control valve 260. 
The gas supply for controlling the actuator 261 is derived from a main gas 
line 266 and an accumulator tank 265 on which is disposed a spool valve 
310. Gas for the accumulator tank 265 is received from the main gas line 
266 through a gas line 303, a check valve 304 and a gas line 305. The gas 
line 303 also connects the main gas line 266 to a pilot or spool valve 310 
(see FIG. 19) and the gas line 305 is also connected to the spool valve 
310. The output from the spool valve 310 appears on a first control gas 
line 314 and a second control gas line 315, both of which are connected to 
the control valve actuator 261. 
A second pipe 270 extends vertically through the mounting plate 247 and the 
shell 211 of the tank and into the body thereof and teminates in an open 
end a short distance below the top of the associated tank. A coupling 271 
connects the lefthand conduit section 221 in FIGS. 13 and 14 to one of the 
inputs to a second control valve 280, the second pipe 270 being also 
connected as an input to the valve 280, and the valves 260 and 280 being 
interconnected by a coupling 275. An actuator 281 is provided for the 
control valve 280, the actuator 281 being of the pneumatic type. The 
control valve 280 in the first or normal position thereof serves to 
provide a passage from the coupling 275 through the control valve 280 to 
the lefthand conduit section 221 while blocking flow to the second pipe 
270. In the second or load/unload position of the valve 280, a passage is 
provided from the second pipe 270 through the valve 280 and to the 
lefthand conduit section 221, while blocking passage through the coupling 
275 to the right from the control valve 280. The control gas lines 314 and 
315 both also connect with the actuator 281, whereby the actuators 261 and 
281 are actuated in synchronism under the control of the spool valve 310, 
thus serving to control the positions of the control valves 260 and 280 
substantially at the same time. 
There also is provided in FIG. 15 a safety valve 285 which provides an 
outlet for gases within the associated tank if the pressure therein rises 
above the predetermined level set by the safety valve 285. There also is 
provided a liquid level sensor 295 which senses the unloaded condition of 
the associated tank and either of two loaded conditions thereof, the first 
being a lower or "summer" level loaded condition and the second being a 
higher or "winter" level loaded condition, the level of both loaded 
conditions being below the lower open end of the second pipe 270, thus to 
control the outage or free vapor space in the filled tank car. 
Referring to FIGS. 19 and 20, there is illustrated the electrical-pneumatic 
control system 300 for controlling the positions of the control valves 260 
and 280, and specifically the associated valve actuators 261 and 281 
therefor, respectively. A solenoid control valve 301 is provided including 
an operating solenoid 302 having input conductors 425, one or the input 
ports of the solenoid control valve 301 being connected to the main gas 
line 266, while one of the outlet ports is connected to a gas line 303, 
and the other two outlet ports are connected to a gas line 306. The gas 
line 303 is connected as one of the inputs to a spool valve 310 that 
controls the valve actuators 261 and 281. The spool valve 310 includes the 
usual spool 312 and a return spring 313. One of the outlet ports of the 
spool valve 310 is connected to the gas line 314, while the other two 
outlet ports are connected to the gas line 315. As has been explained 
heretofore, the gas line 314 is also connected as one of the inputs to the 
valve actuators 261 and 281 while the gas line 315 is connected to the 
other of the inputs to the valve actuators 261 and 281. The accumulator 
265 is also charged with gas under pressure from the main gas line 266 
through the solenoid control valve 301 and the gas line 303. More 
specifically, the gas line 303 is connected to a check valve 304 with the 
outlet of the check valve 304 being connected by a gas line 305 to the 
first connection to the accumulator 265. A second connection to the 
accumulator 265 is made by a gas line 308 which is connected to the gas 
line 306 through the check valve 307. 
When an unloaded tank car is to be loaded with liquified compressed gases, 
the control valves 260 and 280 are initially closed and there is no 
connection to the main gas line 266 and there is no electrical connection 
to the conductors 425 connected to the solenoid control valve 301. The 
first step in the loading operation is to connect a supply of gas under 
pressure, preferably an inert gas such as nitrogen, to the main gas line 
266. The conductors 425 are connected to a terminal control system such as 
the terminal control system 420 described above with respect to FIG. 1. 
The solenoid control valve 301 is initially in the position illustrated in 
FIG. 19, and accordingly upon connection of the gas supply to the main gas 
line 266 (at 90 p.s.i.g. or higher pressure), the line 266 is connected 
through the solenoid control valve 301 to the lines 303. The accumulator 
265 is charged through the check valve 304 and the line 305 to essentially 
the pressure in the line 266. The pressure in the line 266 is also 
conveyed through the line 303 to place the spool valve 310 in the position 
illustrated. The pressure from the line 305 is applied through the spool 
valve 310 to the line 314, thus moving the valve actuators 261 and 281 to 
the open positions thereof, thus opening the associated valves 260 and 
280, respectively, and thus opening the associated pipes 250 and 270, 
respectively, while closing the lading conduit at the coupling 275 
therebetween. It is noted that the line 315 is vented at the spool valve 
310 which is held in the position illustrated in FIG. 19 against its 
spring 313 by the pressure in the line 303. 
Upon the associated fluid level sensor 295 detecting the loaded condition 
of the associated tank car, a signal is sent thereby to a terminal control 
system such as the terminal control system 420 in FIG. 1 and a return 
signal is received from the conductors 425 to shift the solenoid control 
valve 301 from the position illustrated in FIG. 19 to the position 
illustrated in FIG. 20. The main gas line 266 is now connected through the 
solenoid control valve 301 to the line 306 and the line 303 has no 
pressure applied thereto from the main line 266. Since there is no 
pressure applied to the line 303, the spring 313 in the spool valve 310 
returns the spool 312 to the right as viewed in FIG. 20 and this connects 
the line 305 through the spool valve 310 to the line 315 and thus to 
pressurize the line 315. This serves to move the valve actuators 261 and 
281 to close the associated valves 260 and 280, and thus to close the 
associated pipes 250 and 270, while opening the associated lading conduit 
therebetween. It is noted that the line 314 is not pressurized and is 
vented, thus allowing the closing of the valves 260 and 280. The pressure 
in the line 308 continues to charge the accumulator 265 to essentially the 
same pressure as in the main gas line 266. Since the spool 312 of the 
valve 310 is held in the position illustrated in FIG. 20 by the spring 
313, gas from the accumulator 265 can also enter the line 315 to urge the 
valves 260 and 280 to the closed positions thereof. 
Referring to FIGS. 1, 7-10, 19 and 20, a typical loading cycle using the 
loading system 400 to load a string of tank cars equipped with the control 
valves 260 and 280 and the valve control mechanism 300 will be described 
in detail. The string of tank cars 100A to 100C in FIGS. 7-10 is equipped 
with control valves 260 and 280 and a valve control mechanism 300 on each 
tank car (rather than the valves 160, 180 and 190 and the valve control 
mechanism 200 illustrated therein) and arrives in position on the rails 55 
in an unloaded condition. The free end of the lading conduit disposed to 
the right has a cap thereon closing that end of the lading conduit and the 
lefthand end of the lading conduit also has a cap thereon. The cap on the 
righthand end of the lading conduit is removed and the loading conduit 60 
is coupled thereto, and the cap on the lefthand end of the lading conduit 
is removed and the vapor line or conduit 65 is attached thereto. It will 
be appreciated that although the tank cars 100A to 100C are unloaded, 
there still remains therein a quantity of liquified compressed gas or at 
least the vapors thereof, which may typically have a pressure on the order 
of 100 p.s.i.g., whereby upon opening of the valves associated therewith 
an immediate pressure on the order of 100 p.s.i.g. is provided at the end 
of the conduits 60 and 65. The conduit 60 is connected to the outlet of 
the valve 408 for the pump 405 while the conduit 65 is connected to the 
input to the vapor recovery system 415. Accordingly, the entire system 
will immediately be under pressure on the order of 100 p.s.i.g. and there 
will be a minimal introduction of air or oxygen to the system, thus 
minimizing the likelihood of a fire of explosion. The nitrogen supply 410 
is connected through the valve 413 to the main gas line 266 and pressure 
is applied thereto on the order of 90 p.s.i.g. Finally, the conductor 425 
is connected to the solenoid control valves 301 and the conductor 426 from 
the terminal control system 420 is connected to the liquid level sensors 
295. 
When the tank cars 100A to 100C arrive for the loading operation, all of 
the control valves 260 and 280 are closed. Furthermore, the solenoid 
control valves 301 are in the position illustrated in FIG. 19 and the 
spool valves 310 are in the positions illustrated in FIG. 20 of the 
drawings. When the nitrogen supply 410 is connected to the main gas line 
266, and the valve 413 opened, the high pressure gas will be directed by 
the solenoid control valves 301 to the lines 303 which will immediately 
begin charging the associated accumulators 265 and will move the spools 
312 against the springs 313 in the spool valves 310 so as to connect the 
lines 305 to the lines 314. This will cause the valve actuators 261 and 
281 to move so as to open the associated control valves 260 and 280 on all 
the cars in the train 50, the lines 315 being vented to the atmosphere 
through the spool valves 310. 
Fluid lading, such as liquified petroleum gas, is now pumped from the 
supply 401 through the outlet pipe 402, the open valve 403, the pipe 406 
via the pump 405 and then through the pipe 407 and the open valve 408 to 
the loading conduit 60 and then into the lading conduit 220. The fluid 
lading flows through the open valve 260A and down through the first pipe 
250A and into the interior of the associated tank car 100A. The valve 280A 
is also open and the valves 260A and 280A close the lading conduit 
therebetween, whereby the fluid lading flows only through the first pipe 
250A. The vapors generated during the loading operation of the tank car 
100A pass upwardly through the second pipe 270A, and into that portion of 
the lading conduit disposed to the left of the control valves 260A and 
280A and into the next tank car 100B, thus to vent and to equalize the 
pressure that might be therein. Since the valves 260 and 280 on the tank 
cars to the left of the tank car 100A are all open so as to close the 
lading conduit therebetween, the vapors will pass from car to car 
continually venting vapors therefrom and will exit through the vapor 
conduit 65 and thus to the input to the vapor recovery system 415. The 
recovered liquified compressed gas from the vapor recovery system 415 is 
conveyed by the pipe 416 to the input of the supply 401 of liquified 
compressed gas. 
When the fluid level in the tank 110A reaches a predetermined point, the 
liquid level sensor 295A is activated and generates a control signal that 
is conveyed by the conductor 426 to the terminal control system 420. The 
terminal control system 420 in turn creates a control signal that is 
conveyed by the conductors 425 and is applied to the solenoid control 
valve 301 on the car 100A to move the parts thereof to the positions 
illustrated in FIG. 20. The main gas line 266 is now connected to the line 
306 and through the check valve 307 to the line 308, whereby further to 
charge the accumulator 265. Pressure has been removed from the spool valve 
310 and therefor the spring 313 moves the spool 312 to the position 
illustrated in FIG. 20 which vents gas pressure from the line 314 and 
applies gas under pressure from the line 305 to the line 315. This serves 
to move the valve actuators 261 and 281 to positions to close the 
associated valves 260A and 280A, respectively, and thus to close the pipes 
250A and 270A, while opening the lading conduit therebetween. The tank car 
100A is now loaded and the loading operation shifts to the car 100B since 
the valves 260B and 280B are open therein and the lading conduit disposed 
therebetween is closed thereby. 
The liquified compressed gas now flows from the supply 401 under the urging 
of the pump 405 and through the open valves 403 and 408 into the loading 
conduit 60 and through the lading conduit on tank car 100A and into the 
righthand portion of the lading conduit on tank car 100B. Since the 
control valves 260B and 280B are open, the lading conduit therebetween is 
closed, and the lading is diverted and flows through the pipe 250B. The 
tank car 100B is then loaded in the same manner as was tank car 100A 
described above. When the tank car 100B is fully loaded, the liquid level 
sensor 295B senses the fully loaded condition and sends a signal by the 
conductor 426 to the terminal control system 420 which in turn generates a 
control signal that is conveyed along the conductors 425 to the solenoid 
control valve 301 associated with the tank car 100B. Actuation of the 
solenoid control valve 301 on the tank car 100B closes the control valves 
260B and 280B, thus closing the associated pipes 250A and 270A and opening 
the lading conduit therebetween. 
With the control valves 260A, 280A, 260B and 280B closed, a passage is now 
completed from the pump 405 through the valve 408 and the loading conduit 
60 and through the lading conduits on the tank cars 100A and 100B and the 
associated connecting conduits to the righthand end of the lading conduit 
on the tank car 100C. The control valves 260C and 280C are open to open 
the associated pipes 250C and 270C while closing the lading conduit 
therebetween. Accordingly, the fluid lading is loaded into the tank car 
100C through the first pipe 250C. Loading of the tank car 100C proceeds as 
described above with respect to the loading of the tank cars 100A and 100B 
until the liquid level sensor 295C senses the loaded condition of the tank 
car 100C. At this time the liquid level sensor 295C will produce a signal 
conveyed by the conductor 426 to the terminal control system 420 which in 
turn will generate a control signal conveyed by the conductors 425 to the 
solenoid control valve 301 on the tank car 100C. This will shift the 
solenoid control valve 301 on the tank car 100C from the position 
illustrated in FIG. 19 to that illustrated in FIG. 20. This will close the 
control valves 260C and 280C thus closing the associated pipes 250C and 
270C while opening the lading conduit 220C therebetween. The string of 
cars at the loading system 400 is now completely loaded. 
The lading conduits on the tank cars 100A, 100B and 100C are now purged of 
liquid and vapor. This is accomplished by closing the valve 408 and 
opening the valve 412, thus to supply nitrogen gas from the supply 410 
thereof through the outlet pipe 411, the now open valve 412 and the 
loading conduit 60 and through the lading conduits outwardly through the 
conduit 65 to the inlet of the vapor recovery system 415. It will be 
understood that all of the valves 260 and 280 are closed at this time to 
close the associated pipes and to open the associated lading conduits 
therebetween, the solenoid control valves 301 being in the positions 
illustrated in FIG. 20. After the purging, the valve 412 is closed and the 
loading conduit 60 is disconnected from the righthand end of the lading 
conduit and a cap is placed thereon. Likewise, the conduit 65 is removed 
from the lefthand end of the lading conduit and a cap placed on the free 
end of the lading conduit. The connection between the valve 413 and the 
main gas line 266 is removed and the conductors 425 and 426 are 
disconnected from the adjacent car 100A. Disconnection of the gas supply 
from the main gas line 266 removes the pressure from the line 306 (see 
FIG. 20). Summarizing, all the valves 260 and 280 along the entire length 
of the train 50 are now in the closed positions thereof. These valves all 
remain in the closed positions during the transport of the train 50 to the 
point of unloading. 
Referring to FIGS. 2, 11-14, 19 and 20, a typical unloading cycle using the 
unloading system 500 to unload a train of tank cars 100 equipped with the 
control valves 260 and 280 and the valve control mechanisms 300 will be 
described in detail. When the loaded tank cars arrive on the tracks 55 in 
FIG. 2, the solenoid control valves 301 are in the positions illustrated 
in FIG. 20, and since no pressure is applied to the line 266, all of the 
valves 260 and 280 are closed and are further urged into the closed 
positions by the air pressure provided from the accumulator 265 through 
the line 315. The unloading conduit 80 is connected to the righthand end 
of the lading conduit and is connected to the valve 505 and the line 502 
to the inlet for the container 501 of liquified compressed gas. The 
conductor 525 from the terminal control system 520 is connected to the 
conductors for the solenoid control valves 301 and the conductor 526 is 
connected to the liquid level sensors 295. The supply 510 of nitrogen 
under pressure is connected by the pipe 511 through the valve 513 to the 
main gas line 266. Finally the valve 519 is connected to the unloading 
conduit 85 attached to the lefthand end of the lading conduit 120C. Upon 
opening of the valve 513, pressure will be applied to the line 266 and as 
is best illustrated in FIG. 20 of the drawings, pressure will then be 
applied through the solenoid control valves 301 to the lines 306 which 
through the check valves 307 and the lines 308 charge the accumulators 
265. The lines 305 are also connected to the spool valves 310 to 
pressurize the lines 315, thus to hold the valve actuators 261 and 281 and 
the associated valves 260 and 280 closed. Opening of the valves 518 and 
519 now applies the commodity gas vapors under pressure from the 
compressor 515 to the lefthand end of the lading conduit 120C. 
At this time the operator causes a control signal to be generated by the 
terminal control system 520 and conveyed along the conductor 525 to the 
solenoid control valve 301 on the tank car 100C. This control signal 
shifts the solenoid control valve 301 from the position illustrated in 
FIG. 20 to that illustrated in FIG. 19. As a consequence, the control 
valves 260C and 280C are opened, thus to open the associated pipes 250C 
and 270C and to close the lading conduit 220C therebetween. The fluid 
lading is then forced by the pressure of the supply 510 from the tank 100C 
up through the pipe 250C and into the righthand portion of the associated 
lading conduit and then through the interconnected lading conduits on the 
tank cars 100B and 100A and the associated connecting conduits 230 to the 
right and to the unloading conduit 80. This action will continue until the 
tank car 100C is unloaded, it being noted that the lading therefrom flows 
directly into the container 501 without entering any of the other tank 
cars in the train 50. 
When the tank car 100C is unloaded, the liquid level sensor 295C is 
activated and generates a control signal that is conveyed by the conductor 
526 to the terminal control system 520. The terminal control system 520 in 
turn creates a control signal that is conveyed by the conductors 525 and 
is applied to the solenoid control valve 301 on the tank car 100B which 
shifts the solenoid control valve 301 on the tank car 100B from the 
position illustrated in FIG. 20 to the position illustrated in FIG. 19. As 
a consequence, the control valves 260B and 280B are opened, thus to open 
the associated pipes 250B and 270B while closing the associated lading 
conduit therebetween. The fluid lading is then forced by the pressure of 
the supply 510 from the tank 110B up the pipe 250B and into the righthand 
portion of the lading conduit and then through the interconnecting lading 
conduit on the tank car 100A and the associated connecting conduit 130 to 
the right and to the unloading conduit 80. This action will continue until 
the tank car 100B is unloaded, it being noted that the liquid lading 
therefrom flows directly into the container 501 without entering any of 
the other tank cars in the train 50. 
When the tank car 100B is unloaded, the liquid level sensor 295B is 
activated and generates a control signal that is conveyed by the conductor 
526 to the terminal control system 520. The terminal control system 520 in 
turn creates a control signal that is conveyed by the conductors 525 and 
applied to the solenoid control valve 301 on the car 100A to move the 
parts thereof from the positions illustrated in FIG. 20 to the positions 
illustrated in FIG. 10. As a consequence, the control valves 260A and 280A 
are opened, thus to open the associated pipes 250A and 270A while closing 
the lading conduit 220A therebetween. The fluid lading is then forced by 
the pressure of the supply 510 from the tank 110A up through the pipe 250A 
and into the righthand portion of the lading conduit 220A and then to the 
unloading conduit 80. This action will continue until the tank car 100A is 
unloaded, it being noted that the lading therefrom flows directly to the 
container 501 without entering into the other tank cars on the train 50. 
With all the tank cars 100A, 100B and 100C now unloaded, it will be noted 
that the valves 260A, 260B, 260C, 280A, 280B and 280C are all open. 
Disconnection of the valve 519 from the unloading conduit 85 and 
disconnection of the nitrogen supply 510 from the main gas line 266 leaves 
the control solenoids 301 in the position illustrated in FIG. 19 and 
removes pressure from the lines 303, whereby the spool valves 310 are 
returned by the springs 313 to the position illustrated in FIG. 20. The 
pressure in the accumulators 265 applied through the lines 305 to the 
lines 315 moves the valve actuators 261 and 281 and the associated control 
valves 260 and 280 all to the closed positions. The control valves 260 and 
280 now effectively close the associated pipes 250 and 270 and open the 
associated lading conduits along the entire length thereof. The valves 260 
and 280 will remain in the closed positions thereof during the transport 
of the unloaded train 50 to the point of loading. 
Tank cars equipped with the control valves 260 and 280 and associated valve 
control mechanism 300 illustrated in FIGS. 15, 16, 19 and 20 generally 
have the benefits and advantages of the tank cars described above with 
respect to FIGS. 3-14, 17 and 18. 
While there have been described what are at present considered to be the 
preferred embodiments of the invention, it will be understood that various 
modifications may be made therein, and it is intended to cover in the 
appended claims all such modifications as fall within the true spirit and 
scope of the invention.