NOTE- TOTAL 6 QUESTION ARE TO BE ANSWER i.e. FROM PART-A AND FROM PART-B ALL QUESTION CARRY EQUAL MARKS OF 25.
PART –A Q.1
1.1 what are the condition to be fulfilled before granting the line clear to the block station ahead in case of double line section provided with multiple aspect colour light signaling under absolute block system of working?
10 marks
G. R. NO 8.01
4. No train should leave the block section unless line clear received from the block section in advance.
5. on double line such line clear shall not be given unless the line clear upto first stop signal but adequate distance beyond it .
6. on sigle line such line clear shall not given unless the line is clear of trains running in same direction not only upto first stop signal at block station at which such line clear is given but an adequate distance beyond it . and is clear of the trains running in direction towards the block section to which line clear is given condition for granting the line
clear-8.02 class A – line clear may not be given for train unless the line on which it is intended to receive is clear for 400 m beyond home signal or upto the starter signal.
8.02 class B – where the line clear is given for the train before the line has made clear for the reception of the train with in the station section.
8.03 class c – station where the permission to approach may not be given for the train unless whole last train proceeding passes completely at least 400m beyond the home signal and is continuing its journey . this include the IBS.
1.2 What are the rules to be observe by a driver for passing an automatic signal at red aspect? In what way they different from the rules governing passing IBS home
at red aspect ? 10 marks
Automatic signal at red-
‘A” marker is on. Train stops at the bottom of the signal for 1 minute in day and 2 minute in night . whistle prescribe code and exchange the signal with guard and proceed slowly excursing the great caution so as to stop in short of any obstruction, train may resume the running only after passing the OFF aspect of signal.
IBS at on –stop and wait for 5 minute at foot of signal exchange the private number through talk back and proceed . if talk back is defective then whistle proper code
exchange the signal with guard and proceed with cautious speed assuming that train is
ahead if home signal is green he should stop after passing home signal and inform to Dyss and ensure the signal and proceed.
1.3 why and where slip and catch siding are provided? 5 marks the gradient with station has to be very low in order that the vehicle standing at the station do not start moving automatically due to effect of gravity . on Indian railway the gradient permitted is 1:400 where as 1:1200 recommended.
No station is constructed on the gradient steeper than 1:260 except the
geographical condition where such gradient can’t be avoided within station yard. Previous sanction of CRS has to be obtained and special arrangement like slip sideing has to be provided where the gradient steeper than 1:100 falling away from the station in its close neighborhood. This prevent the vehicle from escaping into block section
Similar arrangement where gradient steeper than 1:80 falling towards the station, to trap the vehicle coming uncontrolled toward station from block section is known as the catch siding
Catch siding and slip siding points must be interlocked with block instrument.
Q.2
2.1 What is the schedule of painting for mechanical signaling equipment ? What is the schedule of overhauling of signaling relay and block instruments? 10 marks schedule of
painting-signal arms, indicator in conventional colour – once in year
app in cabin signal post, cabin lever& outdoor gear – once in three year ground gear, rodding roller - once in six year overhauling of relay
track relay - 10 years line relay - 15 years
1:75
1:75 level Catch siding
plug in type - no overhauling BPR relay - 7 years
Block instrument
Token -single line 10 years Tokenless -no overhauling Double line - 7 years
2.2. what is meant by total failure of communication how are gtrains moved from one station to another in case of total failure of communication in single line section
15 marks Q.3
3.1 what are the different types of overhead wires and indoor and underground cables used in railways for telephone exchange to subscriber connection and control and block
working in RE and NON-RE areas? 15 marks
3.2 in mid section an interlocking gate is provided with independent signals . show the signal in form of sketch by marking the inter signal distance for single line section both for
LQ and MACLS territory. 10 marks
Q.4
4.1 in double line section with MACLS and double distant provision show the chart for various combination of aspect of distant signal and meaning they convey to the driver.
DISTANT INN.DIST HOME STARTER MEANING
YY Y R R HOME SIGNAL RED DRIVER HAS STOP
G YY Y R TRAIN ADMITTED ON MAIN LINE
YY YY YwR R TRAIN ADMITTED ON LOOP LINE
YY YY YwR Y TRAIN ON L/L WITH THROUGH SIG.
G G YY Y TRAIN M/L THROUGH SIGNAL
G G G G MAIN LINE THROUGH SIGNAL
10 marks
4.2 give the expansion for the following abbreviation. 5 marks
a) UNO – united nation organisation b) RBI – reserve bank of india
c) ICF – integrated coach factory-perambur d) DLW – disel locomotive workshop
e) NCR – button checking relay
4.3 why are calling on signal provided? What are the conditions under which a calling on signal cleared for train movement? In what ways a calling on signal
differs from the shunt signal. 10 marks
for admitting the train with main signal it is essential that track must be clear not only up to first stop signal but also an adequate distance beyond it .
if one has to admit the train on obstructed line it is not possible to admit the train with main signal. It requires the piloting from the home signal , piloting takes lot of time to avoid this co-on signal is provided .
for taking co-on signal ,all the points must set in route. OV is not required in double line ,in single line OV must set. Train to be admitted on the obstructed track must occupies approaching track , route must set then it is possible to clear the co-on signal.
The shunt signal authorizes the driver to pass the signal at slow speed
irrespective whether the line is occupied or not where there are frequent movement the shunt signal are used. The movements with shunt signal are carried out in the station limit. Shunt signal authorizes the driver to draw ahead with the caution even though the stop signal is at on. For the shunt signal overlap is not necessary.
PART – B Q.1
1.1 what is meant by resonance in a AC series and parallel circuit? How is the resonant frequency calculated in a series and parallel circuit? 10 marks
when the resistance , inductance, capacitor connected in series across A. C. source . if sunisoidal voltage of variable frequency is applied across r-l-c it encounter the different frequency .as frequency is increased XL increases and Xc decreases. There is certain frequency of applied A.C. voltage for which XL=Xc
it is called as the resonance frequency and circuit is said to be in electrical resonance and impedance offered in the circuit is lowest R.
therefore Imax= V/R XL=Xc 2ΠfL=1/2ΠfC f=1/2Π(lc)1/2
Capcitor in parallel with coil with negligible resistance
When XL=Xc
Frequency is called as the resonance frequency
When the two branches current is equal and opposite and current drawn from the supply is zero. In practical it is not zero. Minimum resistance is offered.
1.2 state kirchoff’s law. 5 marks
kirchoff’s current law – in any network of the conductor algebric sum of the current meeting at the point (junction) is zero.
VVVVVV
S
VVVVVV
S
I1- I2+I3+I4-I5=0 Iin=Io
Kirchoff’s voltage law – algebric sum of all IR drops and EMF in closed loop(or mesh) of network is zero.
∑ IR + ∑EMF= 0
1.3 explain what is meant by hysterisis in case of magnetic properties of material subjected to magnetization by electric current. 5 marks suppose the exciting coil of electromagnet is energized by alternating current. As the current reverse the direction of flow through the coil , the flux also reverse . hence core also undergoes the reversal of magnitision but the magnetisetion of the core does not reverse quickly as the reversal of flux. This phenomenon is called as hysterises
1.4 what is meant by stress and strain in the case of material and how are they
related to each other 5
marks
when force is applied over any physical matter
the internal restoring force per unit area is called as the strain
stress= internal resoring force/area
the ratio of change in dimension to the original dimension is called as strain B - FLUX
MAGNETISON FORCE
strain= change in dimension/original dimension
stress is directly proportional to strain this is known as hook’s law
modulus of elasticity=stress/strain Q.2
2.1 what are the component of lead-acid cell? What are the various mode of charging them. What precaution are to be taken in form of ‘DOs’ and “DON”Ts for
charging their up-keep? 15 marks
2.2 what is current transformer where it is used? 5 marks
the transformer used in power eng. For the measurement of current in high voltage circuit is called as the current transformer.
Primary is connected in series with high voltage cuircuit iand sec. having large no. of turns the ammeter is connected.
This principle is used for indication transformer. These transformers are used in the indication circuit.
2.3 what is mean by UPS? Explain the principle of its working 5 marks uninterrupted power supply
UPS- consist of the convertor - A.C.to DC
Invertor - DC to AC
Stabalisr - to stabilize the output Battery bank - of VRLA backup Transfer switch
ON LINE
Ferroresonanat voltage stabaliser connected as hot stand by Uninterrupted power supply output is connected to load
Rectifier or battery charger supplies the required current to invertor in addition to battery bank.
Invertor draws the required load current from the battery charger and in case of the failure of battery charger output , it draws the current from the battery bank.
In case OF OUTPUT from the invertor. Transformer switch will make automatic changeover to FRVS in 50 m/sec.
FERRO. V STAB.
TRANSFER SWITCH INVERTOR
RECTIFIER
BATTERY BANK
BLOCKING DIODE/SWITCH
OFF LINE UPS
UPS act as hot standby
FRVS is connected to load
Battery charger keeps the battery in full charged condition
In case of failure of FRVS output sensec electronically by transferring the switch. So automatic changeover to UPS(alternative source) with 50 m/sec. load is then
connected to invertor Q.3
3.1 explain the working of snubbing circuit of electrical point machin with the help of
circuit digram. 10 marks
3.2 draw the symbol for the following gates with their truth table
AND, EXOR, NOR 6 marks
A
C
B OR GATE BATTERY CHARGER
FERRORESONANT TYPE VOLTAGE STABILISER
INVERTOR
BATTERY B
A
A B C 0 0 0 1 0 0 0 1 0 1 1 1
3.3 how the analogue voice signal digitized in case of telecom equipment like multiplexing? What are the essential diffence between an analogue microwave radio transmission and Digital microwave radio transmission. 9 marks
Q.4
4.1 what is meant by decibel (DB) and DBm?
4.2 explain the difference between RAM and ROM in case of semi-conductor memory?
What is meant by serial and parallel transmission in the case of digital data
communication? 5 marks
4.3 draw the schematic arrengment of power supply for typical way station with panel interlocking for either a RE or a non RE area. Show in it the various power supply equipment/battries in form of block digram. 15 marks
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm m