Single e- per event thrown at mid rapidity, originating at x=0.1, y=0.2, z=3.0 cm.

Track is allowed to propagate out to a radius of 225 cm and then stopped.

-- current  -----------------------------------
path = /HALL_1/CAVE_1/IDSM_1/PIPI_1/PIHI_1
isvol = 0
istracking = 2

event = 1
track = 0
pdgid = 3
flags = 0x0007
 step = 0
astep = 0
 tof  = 0
 dest = 0
adest = 0
xyz   = 0.1/0.02/3
pxyz  =-0.379406/0.856372/0.374782

process in step:
0 secondaries via unknown

New vertex created:
vertex      : 0 @0xfbf4af0
  mechanism : kNull
  x/y/z/t   : 0.1/0.02/3/0
  parents   :
  daughters :

In this first tracking step, we see the state places the track initially at the primary vertex, and a new vertex is created.  The vertex is printed out during its creation,  before the link to the parent particle is set.

-- current  -----------------------------------
path = /HALL_1/CAVE_1/IDSM_1/PIPI_1/PIHI_1
isvol = 0
istracking = 2

event = 1
track = 0
pdgid = 3
flags = 0x0011
 step = 2.1767
astep = 2.1767
 tof  = 7.26068e-11
 dest = 0
adest = 0
xyz   = -0.721579/1.86638/3.80863
pxyz  =-0.382162/0.855145/0.374782

process in step: kMagneticField kTransportation kContinuousEnergyLoss kMultipleScattering
0 secondaries via unknown

The kid takes its first step through the setup, and we see four physics processes being applied during the step.

-- current  -----------------------------------
path = /HALL_1/CAVE_1/IDSM_1/PIPI_1/PBES_1
isvol = 0
istracking = 2

event = 1
track = 0
pdgid = 3
flags = 0x0005
 step = 0
astep = 2.1767
 tof  = 7.26068e-11
 dest = 0
adest = 0
xyz   = -0.721579/1.86638/3.80863
pxyz  =-0.382162/0.855145/0.374782

process in step:
0 secondaries via unknown

We have reached a volume boundary and we are about to step into the beryllium section.

-- current  -----------------------------------
path = /HALL_1/CAVE_1/IDSM_1/PIPI_1/PBES_1
isvol = 0
istracking = 2

event = 1
track = 0
pdgid = 3
flags = 0x0011
 step = 0.0823534
astep = 2.25905
 tof  = 7.53538e-11
 dest = 0.000194004
adest = 0.000194004
xyz   = -0.752779/1.93619/3.83922
pxyz  =-0.382722/0.855043/0.373921

process in step: kMagneticField kTransportation kContinuousEnergyLoss kMultipleScattering
0 secondaries via unknown

...


-- current  -----------------------------------
path = /HALL_1/CAVE_1/BTOF_1/BTOH_1/BSEC_52/BTRA_1/BXTR_1/BRTC_1/BGMT_1/BRMD_14/BRDT_1/BRIG_4
isvol = 0
istracking = 2

event = 1
track = 0
pdgid = 3
flags = 0x0009
 step = 0.0308864
astep = 231.206
 tof  = 7.7122e-09
 dest = 9.25609e-05
adest = 0.00824566
xyz   = -118.386/177.789/88.8008
pxyz  =-0.639498/0.675075/0.366555

process in step: kMagneticField kContinuousEnergyLoss kMultipleScattering kDeltaRay 
1 secondaries via kDeltaRay

New vertex created: 
vertex      : 1 @0x1051dea0
  mechanism : kDeltaRay
  x/y/z/t   : -118.386/177.789/88.8008/7.7122e-09
  parents   :
  daughters :

Made it out to the BTOF, and our first secondary is created.  A delta ray.  So... let's print out the track...

---

Event tracks

track       : 0 @0xfc03f00
  idstack   : 1
  idpdg     : 3
  idmc      : 0
  px/py/pz/E: -0.379406/0.856372/0.374782/1.00885
  vertices  : 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 

Track is idpdg (actually geant 3 ID here) = 3.  It was created on vertex 0 and terminated on vertex 35, with 34 vertices in between.

vertex      : 0 @0xfbf4af0
  mechanism : kNull
  x/y/z/t   : 0.1/0.02/3/0
  parents   :
  daughters : 0 

kNull usually indicates this was a primary track.   Ideally I want this as kPrimary, but not certain we have full information on this from the state.  TBD.

vertex      : 1 @0x1051dea0
  mechanism : kDeltaRay
  x/y/z/t   : -118.386/177.789/88.8008/7.7122e-09
  parents   : 0
  daughters : 67

This is our first delta ray vertex, corresponding to the vertex created w/in the BTOF.  It has parent track #0, and daughter track #67.

 vertex      : 2 @0xfbb5458
  mechanism : kBremsstrahlung
  x/y/z/t   : -118.535/177.947/88.8865/7.71999e-09
  parents   : 0
  daughters : 66

On the next step, our electron puts on the breaks.

...

vertex      : 35 @0xfbc4be8
  mechanism : kDiscarded (user defined max radius of 225.0 cm).
  x/y/z/t   : -126.518/186.145/93.4015/8.13031e-09
  parents   : 0
  daughters :

Finally we reach the last vertex on the track.  Here, I needed to add in one more piece of logic, as we reached the R=225cm max radius where I manually stop the track.  (Logic should be revisited w/out the STOP condition in place).