Content of a GZ-1 file:

Name	Type	Value	Length (in bytes)	Description
Header Text	char (ANSI)	Any ANSI text (e.g. "Hello, world!")	1-*	ASCII text containing meta-info about the file
Header End	byte	0x1A	1	Marks the end of the Header Text
File Identifier	char	0x47, 0x5a, 0x47 ('G', 'Z', 'G')	3	Static text "GZG" used to identify GZ-* files
Zoom Factor	char	0x49 ('1')	1	Zoom factor as char. '1' for GZ-1 files, '2' and '4' for GZ-2 and GZ-4 respectively
Version	byte	0x03, 0x84	2	Version of Bahn
Sub-version	byte	0x00, 0x03	2	Sub-version of Bahn
Properties	int32	bitmask	4	See Flags below
Steam/Smoke origin X *	int32	any int32	4	X position of the smoke origin. Only set when either the steam- or smoke-flag is set
Steam/Smoke origin Y *	int32	any int32	4	Y position of the smoke origin. Only set when either the steam- or smoke-flag is set
Steam/Smoke origin Width *	int32	any int32	4	Width (length) of steam/smoke. Only set when either the steam- or smoke-flag is set
Clock future flag *	int32	1	4	For future use. Set to 1 if clock flag is set, otherwise omit
...	...	...	...	...

Flags

Flag	Binary	Hex	Description
Smoke	0000000000000001	0x0001	Element emits smoke (exclusive to Steam)
Steam	0000000000000010	0x0002	Element emits steam (exclusive to Smoke)
Clock	0000000000000100	0x0004	Element contains a clock
Cursor info available	0000000000001000	0x0008	Element contains custom cursor info
Driveway info available	0000000000010000	0x0010	Element contains custom driveway info
Colormap info available	0000000000100000	0x0020	Element contains custom colormap info
24BPP	0010000000000000	0x0200	Encoded in new color format (required)

Example of a flag combination: 00100000 00110010 This means, the element emits steam and contains custom driveway- and colormap info. The 24BPP flag must always be set.