Lecture 3 Final
-
Upload
aastha-soni -
Category
Documents
-
view
228 -
download
1
Transcript of Lecture 3 Final
![Page 1: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/1.jpg)
CE - 363
Lecture – 3: Track Resistances,
Hauling Capacity
Dr. Ankit Gupta, Assistant Professor
Department of Civil Engineering
National Institute of Technology Hamirpur
![Page 2: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/2.jpg)
Lecture Outline
Resistances to Traction
Hauling Capacity
Tractive effort of a locomotive
Classification of locomotives
![Page 3: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/3.jpg)
Traction
Definition:
The source through which the locomotive
drives power is called traction.
Sources:
Steam
Diesel fuel
Electric supply (AC/DC)
![Page 4: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/4.jpg)
Traction / Power has a bearing up on:
Load carrying capacity
Speed
Economy
Efficiency of service
Traction
![Page 5: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/5.jpg)
Traction - Comparison
Source of energy
Engine (Design/weight)
Overload capacity
Tractive effort available
Power utilization / fuel
consumption
Speeds
Rate of acceleration
Life of locomotive
Direction for use / need
of reversing
Driving skills
Shed requirements
Repairs and renewable
Personnel requirement
Flexibility (No of coaches
attached)
Track riding
Cost
![Page 6: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/6.jpg)
Working hours / day
Monthly kilometrage
Pollution and
hazards (smoke /
fire)
Availability for
service
Suitability (w.r.t. type
of traffic; availability
of fuel / water;
speeds; type of
operation)
Thermal efficiency
Slipping on /
adhesion with track
(of wheels)
Traction - Comparison
![Page 7: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/7.jpg)
Resistances to Traction
Resistances
Rolling
Stock
Track
Profile
Tractive
effort Wind
Speed
independent
Speed
dependent Atmospheric Gradient
Curves
Starting
Acceleration Journal
friction
Rolling
friction
Track
resistance
Internal
part friction
Track
irregularities
Vertical
movement
Flange
action
![Page 8: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/8.jpg)
Train Resistances (due to rolling stock)
Resistances due to track profile
Traction Loss (due to starting and
acceleration)
Wind resistances
Resistances to Traction
![Page 9: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/9.jpg)
Train Resistances
Train Resistances (RT1)
Resistances independent of speed
Resistances dependent on speed
Atmospheric resistances
![Page 10: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/10.jpg)
Resistances independent of speed are caused due to:
Friction imposed due to train components (locomotive, wagons / compartments), known as Journal friction Dependent up on type of bearing, lubricant
used and temperature of atmosphere
For roller bearing – 0.5 to 1.0 kg per tonne
For coupled boxes – 1.3 to 1.5 kg per tonne (Hard grease)
Train Resistances
![Page 11: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/11.jpg)
Resistances independent of speed (Rt1) are caused due to:
Friction between steel wheels and steel rails
Track resistance – wave action of rails
Resistance due to internal parts, e.g. cylinder and rim of driving wheels, etc.
Computation -
Rt1 = 0.0016 w,
where ‘w’ is weight of train in tonnes.
Train Resistances
![Page 12: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/12.jpg)
Resistances dependent of speed (Rt2):
caused due to -
Track irregularities
Vertical movement of wheels on rails
(improper joints and maintenance)
Flange action (oscillations, sways, etc.)
Rc α (1/length) of rigid base, or
Rc α (speed of the train)2
Train Resistances
![Page 13: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/13.jpg)
Resistances dependent of speed (Rt2):
caused due to -
Computed as -
Rt2 = 0.00008 w.v,
where ‘w’ is weight of train in tonnes and
‘v’ is speed of train in km ph.
Train Resistances
![Page 14: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/14.jpg)
Atmospheric Resistances (Rt3):
On sides and end of wagons /
locomotives
Wind is assumed as not blowing.
Computed as -
Rt3 = 0.0000006 w.v2,
where ‘w’ is weight of train in tonnes and
‘v’ is speed of train in km ph.
Train Resistances
![Page 15: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/15.jpg)
Train Resistances (RT1) = Rt1 + Rt2 + Rt3
RT1 = 0.0016w + 0.00008w.v + 0.0000006wv2
Train Resistances
![Page 16: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/16.jpg)
Resistances due to Track Profile (RT2):
Caused due to –
Gradients, and
Curves
Train Resistances
![Page 17: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/17.jpg)
Resistance due to gradient (Rg)
w = weight of train acting at CG
N = Normal pressure on rails
Computed as -
Rg = w tanΘ
N W
Θ Rg
G
Train Resistances
![Page 18: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/18.jpg)
Resistance due to curves (Rc)
Factors controlling are:
Rigidity of wheel base
Wear on inner side of outer rail due to flange of leading axle and inner side of inner rail due to flange of trailing axle, causing mount on rail
In other two cases it tends to derail
Train Resistances
![Page 19: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/19.jpg)
Resistance due to curves (Rc)
Factors controlling are:
Slippage of wheel (longitudinal and transverse)
Insufficient super-elevation: more pressure on inner rail
Extra super-elevation: more pressure on outer rail
Poor maintenance of track and components
Train Resistances
![Page 20: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/20.jpg)
Train Resistances
![Page 21: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/21.jpg)
Train Resistances
![Page 22: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/22.jpg)
Resistance due to curves (Rc)
Resistance increases with increase in
speed
G
R
D2
D1
D
Train Resistances
![Page 23: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/23.jpg)
Resistance due to curves (Rc)
Distance traveled by outer wheel = D1
Distance traveled by inner wheel = D2
Extra distance traveled = D1 – D2
If ‘F’ is the force of sliding friction,
then Work done is = (D1 – D2) F
Mean Resistance = {(D1 – D2) F} / D
= G.α.F / R. α
= F.G / R
Train Resistances
![Page 24: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/24.jpg)
Resistance due to curves (Rc)
Therefore, Resistance gets affected by
Force of sliding friction (F), Gauge of
track (G) and degree of curvature (R)
Recommended values of curve
resistances:
Broad gauge Rc = 0.0004w.D
Meter gauge Rc = 0.0003w.D
Narrow gauge Rc = 0.0002w.D
Train Resistances
![Page 25: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/25.jpg)
Tractive Resistances
Resistances due to Tractive Effort (RSA)
Get induced due to -
Starting operation
Acceleration given to a locomotive
![Page 26: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/26.jpg)
Resistance due to starting (RS)
Varies according to the type of an object
For locomotives RS = 0.15 w1
For vehicles RS = 0.005 w2
where w1 is weight of locomotive in
tonnes, and
w2 is weight of a vehicle in tonnes
Tractive Resistances
![Page 27: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/27.jpg)
Resistance due to acceleration (RA)
Caused due to change in speed with
respect to time
RA = 0.028 w (v2 – v1) / t
Where v1 = velocity at the beginning (km ph)
v2 = velocity at the end (km ph)
t = Time taken in seconds for achieving the
sped from v2 to v1
w = total weight of train in tonnes
Tractive Resistances
![Page 28: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/28.jpg)
Wind Resistances
Resistances due to Wind (RW)
Depends up on -
Direction of wind w.r.t. movement of train
Wind velocity
Sectional area exposed to wind
Direction of Train Movement
V CosΘ
V SinΘ Θ
![Page 29: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/29.jpg)
Resistances to Traction
Resistances due to Wind (RW)
RW = 0.000017 A V2
Where A = exposed area in sq. meters
V = velocity of wind in km ph
Total Resistance to Traction (RT)
RT = RT1 + RT2 + RSA + RW
![Page 30: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/30.jpg)
Hauling Capacity
Defined as the load that can be handled by the locomotive. It is an indicative of power available to a locomotive.
It can be computed as a product of coefficient of friction and weight on the driving wheels.
At the minimum level it should be equal to Traction Resistances.
![Page 31: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/31.jpg)
Hauling Capacity
The factors controlling the capacity are:
Weight coming on the driving wheels, and
Coefficient of friction
It largely depends up on:
Condition of rail surface, and
Speed of the locomotive
![Page 32: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/32.jpg)
Coefficient of friction - value
Condition of rail surface:
Very wet / very dry 0.25
Greasy 0.03
Average dampness 0.166
In tunnels / frosty condition 0.125
With respect to speed it varies between 0.1
at high speeds to 0.2 at low speeds
Hauling Capacity
![Page 33: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/33.jpg)
Hauling Capacity = µ.w.n = µ.W
Where µ = coefficient of friction
w = weight on driving axle
n = number of pairs of driving wheels
W = Total load on driving wheels
Maximum axle load in India
BG = 28.56 tonnes
MG = 17.34 tonnes
NG = 13.26 tonnes
Hauling Capacity
![Page 34: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/34.jpg)
Tractive Effort
It is usually equal to or little in excess of
hauling capacity.
Computed by equating work done by
tractive effort to the total power developed
by the locomotive.
![Page 35: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/35.jpg)
For steam locomotive:
It depends up on
Difference in pressure on two sides of
the cylinder (p)
Length of stroke (L)
Area of piston (a)
Diameter of piston (d)
Diameter of wheel (D)
Tractive Effort
![Page 36: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/36.jpg)
If Te is the mean tractive effort then,
Work done by a two cylinder engine
= 2.p.a.(2L) = π.p.L.d2
Work done in one revolution of driving
wheel = π. D. Te
Therefore, equating the work done
Te= p.d2.L / D
Hence, a small diameter wheel will
increase the tractive effort, but it will
reduce the speed of movement.
Tractive Effort
![Page 37: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/37.jpg)
For diesel locomotive
Te = 308 x HPr / V
Where HPr is rated horse power of the
engine,
V = Velocity in km ph
Tractive Effort
![Page 38: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/38.jpg)
Classification of Locomotives
Classified on the basis of:
Gauge for which manufactured
Type of traction available
Type of load to be carried
These are indicated using an alphabet
![Page 39: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/39.jpg)
Classification on the basis of Gauge for
which manufactured
Broad gauge X or W
Meter Gauge Y
Narrow gauge Z
Classification of Locomotives
![Page 40: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/40.jpg)
Classification on the basis of type of
traction available
Diesel D
AC Electric A
DC Electric C
Classification of Locomotives
![Page 41: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/41.jpg)
Classification on the basis of type of
load to be carried
Light passenger A or L
Standard passenger B or P
Heavy passenger C
Standard goods D or G
Heavy goods E
Mixed goods and passenger M
Shuttle or shunting U / T / W
Classification of Locomotives
![Page 42: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/42.jpg)
Salient features
Identifier Type Axle Load Length (m)
XA 4-6-2 13.2 T 19.2
XB 4-6-2 17.3 T 23.1
XC 4-6-2 20.1 T 23.2
XD 2-8-2 17.3 T 23.3
XE 2-8-2 22.9 T 24.0
YB 4-6-2 16.2 T 18.3
YC 4-6-2 12.2 T --
YD 2-8-2 10.2 T 18.2
ZB 2-6-2 6.1 T 12.8
ZE 2-8-2 8.1 T 14.6
Classification of Locomotives
![Page 43: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/43.jpg)
Common identifiers for different tractions Diesel
BG WDM1, WDM2, WDM4
MG YDM1, YDM2, YDM4
Latest WDG2, WDP1, WDP2
Electric BG WAM1, WAM2, WAM3, WAM4, WAP1
WAG1, WAG2, WAG3, WAG4, WAG5
WCM1, WCM2, WCM3, WCM4, WCG1
MG YAM1
Classification of Locomotives
![Page 44: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/44.jpg)
Classification of Locomotives
![Page 45: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/45.jpg)
Classification of Locomotives
![Page 46: Lecture 3 Final](https://reader033.fdocuments.net/reader033/viewer/2022051706/577cc9df1a28aba711a4d015/html5/thumbnails/46.jpg)
Classification of Locomotives
WAG9