CRN

The evaluation parameter in CRN („Calculation of Railway Noise“) is the level L_Aeq,18h in dB(A) CRN-1995.

Dialog Railway (for CRN)

Emission Parameter

The emission parameter is the A-weighted continuous sound pressure level L_Aeq,25m at a distance of 25 m from the nearside railhead. It calculates from the base line sound exposure level SEL in dB(A) at that distance:

• for rolling railway vehicles (electric locos, cars and wagons):

\(SEL_{vehicle} = 31.2+20 \lg v + \text{vehicle correction} \:\text{in dB(A)}\)

• for diesel locomotives (full power):

\(SEL_{vehicle} = 112.6+10 \lg v + \text{vehicle correction} \:\text{in dB(A)}\)

with

• v: speed (km/h)
• vehicle correction: see subsequent section „Train Types & Type Corrections“

and for N number of identical vehicles:

\(SEL_{tot} = SEL_{vehicle} + 10 \lg N\:\text{in dB(A)}\)

This results in the two levels L_Aeq for Day and Night:

\(L_{Aeq,18h}=SEL_{tot}-48.1+10\lg N_{day}:\text{in dB(A)}\)

\(L_{Aeq,6h}=SEL_{tot}-43.3+10\lg N_{night}:\text{in dB(A)}\)

with

• N_day: number of trains during daytime (6 to 24 hours)
• N_night: number of trains during daytime (0 to 6 hours)

Note

The numerical corrections result from the time correction for 18 hours (10 lg (18*3600s/1s) = 48.1 dB and 6 hours (10 lg (6*3600s/1s) = 43.3 dB.

Track Condition

In case the option „Train Classes and Penalties“ is selected the track correction can be entered manually.

Type of Track	correction (dB)
continuously welded rail on concrete	0
continuously welded rail on wooden sleepers	0
jointed track, points and crossings	+2.5
slab track	+2
concrete bridges and viaducts	+1
steel bridges	+(4 to 9)

Note

For the time being, CadnaA provides no list box for CRN specific track corrections.

Option „Ballast“

CRN specifies a ballast correction of -1.5 dB in case the sleepers are supported by an acoustically absorbing ballast layer (CRN, clause 22 CRN-1995). In CadnaA the following specifications apply:

• CadnaA applies the correction in the propagation, not in the emission (i.e. the emission value L_Aeq,25m is not changing with „Ballast“ on/off).
• The correction applies to single and several parallel tracks as well. This means that the CRN-clause regarding the non-relevance of the ballast correction for single track railways is not considered automatically in CadnaA, but just in case the option is deactivated.
• CadnaA does not apply the ballast correction for screened receivers (i.e. at least one or more barriers are intersecting the ray path).

Note

The CRN specification to not apply the ballast correction „for a locomotive on power“ (must read: „... on/under full power“) has to be ensured by the user by deactivating the option „Ballast“ in this case.

Option „Diesel locomotive full power“

With this option active the „correction for angle of view“ in CRN occurs according to chart 8 (in opposite to chart 7 for other types of trains CRN-1995). CadnaA applies this correction in the emission value L_Aeq,25m.

v_max (km/h)

Based on the track-relevant maximum speed v_max the train speed will be adjusted if necessary. In the calculation the smaller of both values is used.

Geometry

The source height in CRN is the height of the nearside railhead. The default height in CadnaA is 0.6 m relative above ground (see dialog Geometry).

For diesel locomotives at full power, however, it is at 4 m above the nearside railhead. In CadnaA, with the option „Diesel locomotive full power“ activated, 4 m are automatically added to the height specified on dialog Geometry.

Train Types & Type Corrections

In CadnaA, the following types of train and type corrections are available.

Note

The data of the CRN-specific train classes is not available via the local or global libraries, but coded internally.

Train Types CRN

Abbr.	Train Class Name	Corr.dB(A)	Abbr.	Train Class Name	Corr.dB(A)
Mk1	British Rail MkI	14.8	C43	Class 43	18
Mk2	British Rail MkII	14.8	C47	Class 47	16.6
GwEx	Gatwick Express	16.7	C56	Class 56	16.6
C421	Class 421 EMU	10.8	C59	Class 59	16.6
C422	Class 422 EMU	10.8	C60	Class 60	16.6
LUnA	London Undergr-A Stock	12.9	C73	Class 73	14.8
LUnT	London Undergr-Tube stock	7.1	C86	Class 86	14.8
Mk3	British Rail MkIII	6	C87	Class 87	14.8
Mk4	British Rail MkIV	6	C90	Class 90	14.8
C319	Class 319 EMU	11.3	C91	Class 91	14.8
C465	Class 465 EMU	8.4	C20F	Class 20 Full Power	0
C466	Class 466 EMU	8.4	C31F	Class 31 Full Power	0
C165	Class 165 DMU	7	C33F	Class 33 Full Power	0
C166	Class 166 DMU	7	C37F	Class 37 Full Power	0
MML	Manchester Metrolink LRV	15.8	C43F	Class 43 (HST) Full Power	0
SYST	South Yorkshire Supertram	14.9	C47F	Class 47 Full Power	0
2XTW	2 axle tank wagon	12	C56F	Class 56 Full Power	0
4XTW	4 axle tank wagon	15	C59F	Class 59 Full Power	0
MGRC	Merry Go Round Coal Hopper	8	C60F	Class 60 Full Power	0
FL	Freightliner	7.5	C390	Pendolino Brittanico	8.7
C20	Class 20	14.8	C220	Voyager	7.7
C31	Class 31	16.6	C221	Voyager (tilting)	6
C33	Class 33	14.8	C170	Turbostar	7.6
C37	Class 37	16.6

Train Types from DEFRA-report

Abbr.	Train Class Name	Corr.dB(A)	Abbr.	Train Class Name	Corr.dB(A)
C168	168 Turbostar DMU	7.6	C450M	450 Desiro EMU (M)	8.7
C170n	170 Turbostar DMU - new	7.6	C450T	450 Desiro EMU (T)	6
C175	175 Coradia DMU	7.6	C458M	458 Juniper EMU (M)	7.6
C180	180 Coradia DMU	7.6	C458T	458 Juniper EMU (T)	6
C220n	220 Voyager DMU - new	7.6	C460M	460 Gatwick Juniper EMU (M)	7.6
C221n	221 Voyager DMU - new	7.6	C460T	460 Gatwick Juniper EMU (T)	6
C323M	323 EMU (M)	8.7	KQA_l	KQA loaded Pocket wagon	15
C323T	323 EMU (T)	6	KQA_e	KQA empty Pocket wagon	17.5
C332M	332 Heathrow Express EMU (M)	7.6	C92	Class 92 locomotive Dual voltage electric	16.6
C332T	332 Heathrow Express EMU (T)	6	BAA	BAA wagon, Steel carrier, 4 axle	15.2
C333M	333 EMU (M)	7.6	BBA_l	BBA wagon loaded, Steel carrier, 4 axle	13.4
C333T	333 EMU (T)	6	BBA_e	BBA wagon empty, Steel carrier, 4 axle	16.1
C334M	334 Juniper EMU (M)	7.6	BDA_e	BDA wagon empty, Bolster 4 axle	10.8
C334T	334 Juniper EMU (T)	6	BZA_l	BZA wagon loaded, Steel carrier, 4 axle	11.8
C350M	350 Desiro EMU (M)	8.7	MEA_e	MEA wagon empty, Box mineral, 2 axle	5.6
C350T	350 Desiro EMU (T)	6	TDA_l	TDA wagon loaded, Tank, 4 axle	17.8
C357M	357 Electrostar EMU (M)	7.6	TEB_l	TEB wagon loaded, Tank, 4 axle	20.2
C357T	357 Electrostar EMU (T)	6	TIA_l	TIA wagon loaded, Tank, 2 axle	17.8
C375M	375 Electrostar EMU (M)	7.6	HTA_l	HTA wagon loaded, Hopper, 4 axle	7.1
C375T	375 Electrostar EMU (T)	6	HTA_e	HTA wagon empty, Hopper, 4 axle	10.4
C377M	377 Electrostar EMU (M)	7.6	C66	Class 66 rolling, Diesel locomotive	13
C377T	377 Electrostar EMU (T)	6	C66F	Class 66 on-power, Diesel locomotive	-13.4
C390Mn	390 Pendolino Britannico (M) - new	7.6	C67	Class 67 rolling, Diesel locomotive	7.4
C390Tn	390 Pendolino Britannico (T) - new	6	C67F	Class 67 on-power, Diesel locomotive	-10.8
C444M	444 Desiro EMU (M)	8.7
C444T	444 Desiro EMU (T)	6

Suffixes: M=motor vehicle, T=trailer vehicle

Train Classes and Penalties

With this option activated, the types of trains and train classes, numbers of trains and corrections, can be edited locally, or an existing list with number of trains can be selected. CadnaA will automatically calculate the emission level from the specified values.

Note

In the following, the procedure to edit a local train list (with numbers of trains) is described. To enter a train list in the local library, see Common Input Data, Number of Trains.

Local Train List

Train Type

The train type is selected from the list „Type“. By this selection all relevant parameters are specified.

Number of Vehicles

numbers of trains for Day/Evening/Night

Speed v (km/h)

relevant speed of trains (km/h)

Type Correction (dB)

type correction for this train type

Emission L_A25,i (dB)

The emission level L_A25,i for train class i resulting from the specified parameter is displayed here.

Library with Number of Trains

see Common Input Data, Number of Trains