RADIATION RAILWAY SIGNALS WITH RADIOISOTOPES LOCATED ON GROUNDS AND THEIR MECHANISMS OF FAIL-SAFE OPERATIONS

Journal Article · Thu Nov 01 04:00:00 EST 1962 · Radioisotopes (Tokyo) (Japan)

DOI:https://doi.org/10.3769/radioisotopes.11.4_344· OSTI ID:4746659

Kobayashi, A

Preliminary tests on radiation-interraption type railway signals were carried out. These are applicable as traindetectors when the radiatton is traveraing over the track and as axle-counters when the gamma rays are traversing just over the head of rail. A train detector with bremsatrahlung from Kr/sup 85/ and gamma-axle-counters seemed to be most promising. Next the fail- safe mechanism of gamma electronic relay aimed for a radiation cab-signal, in which a radioisotope is buried along tracks and the detector is installed on a train, was developed. This mechanism includes a special pulse circuit called a choking circuit, which consists of a C.R pulse integrator followed by a Schmitt Trigger.'' Normally this Trigger'' is always making flipflop actions through integrator's ripple voltage caused by a G-M tube background pulses. This pulsive power activates the auxiliary relay, indicating all circuit including a C-M tube to be in a good condition. In the case of G-M tube or circuit failures this auxiliary relay drops away. When the signal radiation is reached, the high intensity radiative pulses drive a Schmitt Trigger continuously in a trigged state. In this state, the normally conducting signal-relay current is cut off, and then the signal relay drops away indicating a warning state. Through adequate combinations with the signal and auxiliary relay contacta, the fail-safe relay system was accomplished. (auth)

• Research Organization: Railway Technical Inst., Japan National Railway
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-008507
• OSTI ID: 4746659
• Journal Information: Radioisotopes (Tokyo) (Japan), Journal Name: Radioisotopes (Tokyo) (Japan) Vol. Vol: 11; ISSN RAISA
• Country of Publication: Country unknown/Code not available
• Language: Japanese

Related Subjects

BREMSSTRAHLUNG
CIRCUITS
ELECTRONIC EQUIPMENT
FAILURES
GAMMA RADIATION
GEIGER-MUELLER COUNTERS
INDUSTRIAL APPLICATIONS OF ISOTOPES AND RADIATIONS
KRYPTON 85
MECHANICS
PULSES
RADIOISOTOPES
RAILWAY
RELAYS
SAFETY
SIGNALS