Here's a basic layout of the data structure of the locomotion.loco file.

#include "standard-types.hsl"

#pragma byteorder(big_endian)
#pragma maxarray(65536) 	// max that hw 5.1 will allow
#pragma maxstring(512)

typedef struct LocoEntry1Coords
{
	DWORD	Unknown;
	float	X;
	float	Y;
	float	Z;
} LocoEntry1Coords;

typedef struct LocoEntry1
{
	DWORD	Unknown0;
	char	Name[16];
	DWORD	Unknown1;	// always == 0x0820 ?
	DWORD	Unknowns2[94];
	LocoEntry1Coords	Coords[16];
} LocoEntry1;

typedef struct LocoEntry2
{
	DWORD	Unknowns1[6];
	float	Unknowns2[94];
} LocoEntry2;

typedef struct LOCO		// environment map
{
	DWORD	Unknown1;
	DWORD	Unknown2;
	DWORD	LocoEntry1Size;
	DWORD	LocoEntry2Size;
	DWORD	Unknown3;
	DWORD	Entry1Count;
	DWORD	Entry2Count;
	DWORD	Entry3Count;
	DWORD	StringsSectionSize;
	DWORD	Unknown7;
	
	LocoEntry1	Entries1[Entry1Count];
	LocoEntry2	Entries2[Entry2Count];
	DWORD	Entries3[Entry3Count];
	char	StringsSection[StringsSectionSize];
	
} LOCO;