diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index f297d3b..367cf52 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -31,6 +31,5 @@ jobs:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
       - uses: julia-actions/cache@v2
-      - run: julia -e 'import Pkg; Pkg.Registry.add(Pkg.RegistrySpec(url = "https://github.com/bmad-sim/BmadRegistry.jl"))'
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
diff --git a/Project.toml b/Project.toml
index 8f2276d..a6ad2c1 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,9 +1,10 @@
 name = "AcceleratorLattice"
 uuid = "118f53b2-f4ec-480a-a460-1a04f660b17d"
 authors = ["David Sagan"]
-version = "0.6.2"
+version = "0.6.3"
 
 [deps]
+AcceleratorSimUtils = "8b14b3b2-39c5-4be4-bdc0-0b322e577224"
 Accessors = "7d9f7c33-5ae7-4f3b-8dc6-eff91059b697"
 AtomicAndPhysicalConstants = "5c0d271c-5419-4163-b387-496237733d8b"
 EnumX = "4e289a0a-7415-4d19-859d-a7e5c4648b56"
@@ -14,10 +15,10 @@ PyFormattedStrings = "5f89f4a4-a228-4886-b223-c468a82ed5b9"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 ReferenceFrameRotations = "74f56ac7-18b3-5285-802d-d4bd4f104033"
-SimUtils = "042f21a8-4046-4c2b-b9ed-b6e14110b343"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [compat]
+AcceleratorSimUtils = "0.4"
 Accessors = "0.1"
 AtomicAndPhysicalConstants = "0.5"
 EnumX = "1"
@@ -28,7 +29,6 @@ PyFormattedStrings = "0.1"
 Random = "1.10"
 Reexport = "1.2"
 ReferenceFrameRotations = "3"
-SimUtils = "0.4"
 Test = "1.10"
 julia = "1.9"
 
diff --git a/manual/bookkeeping.tex b/manual/bookkeeping.tex
index 78a2193..0fd65b6 100644
--- a/manual/bookkeeping.tex
+++ b/manual/bookkeeping.tex
@@ -5,6 +5,11 @@ \chapter{Lattice Bookkeeping}
 This includes dependent parameters within a lattice element, propagating changes through the lattice,
 and lord/slave bookkeeping.
 
+Note: An element in a branch has a pointer to the branch (\vn{Ele.branch}) and the branch has
+a pointer to the lattice (\vn{Branch.lat}). So a lattice element ``knows'' about the lattice it
+is in. On the other hand, elements in beam lines don't have pointers to the beamline. This is 
+an important factor when setting up forks.
+
 %---------------------------------------------------------------------------------------------------
 \section{Lord/Slave Bookkeeping}
 \label{s:lord.slave.book}
diff --git a/src/AcceleratorLattice.jl b/src/AcceleratorLattice.jl
index f434a36..2fdb023 100644
--- a/src/AcceleratorLattice.jl
+++ b/src/AcceleratorLattice.jl
@@ -17,7 +17,7 @@ using EnumX
 using Random
 using OrderedCollections
 using Reexport
-@reexport using SimUtils
+@reexport using AcceleratorSimUtils
 @reexport using AtomicAndPhysicalConstants
 
 # AtomicAndPhysicalConstants
@@ -84,7 +84,4 @@ export rotX, rotY, rotZ, rot, rot!, bend_quaternion, lat_ele_dict
 # From LinearAlgebra
 export norm
 
-# From SimUtils
-export one_cos, modulo2, un_sinc, cosc
-
 end # module
diff --git a/src/bookkeeper.jl b/src/bookkeeper.jl
index f5ad270..0baed17 100644
--- a/src/bookkeeper.jl
+++ b/src/bookkeeper.jl
@@ -143,7 +143,7 @@ function bookkeeper_ele!(ele::Ele, changed::ChangedLedger, previous_ele::Ele)
     if !haskey(ELE_PARAM_GROUP_INFO, group) || !ELE_PARAM_GROUP_INFO[group].bookkeeping_needed; continue; end
 
     try
-      elegroup_bookkeeper!(ele, group, changed, previous_ele)
+      ele_paramgroup_bookkeeper!(ele, group, changed, previous_ele)
     catch this_err
       reinstate_changed!(ele, group)    # Try to undo the dammage.
       rethrow(this_err)
@@ -383,20 +383,20 @@ function param_conflict_check(ele::Ele, syms...)
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{T}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{T}, ...)
 # Essentially no bookkeeping is needed for groups not covered by a specific method.
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{T}, changed::ChangedLedger, 
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{T}, changed::ChangedLedger, 
                                       previous_ele::Ele) where T <: EleParams
   clear_changed!(ele, group)
   return
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{BMultipoleParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{BMultipoleParams}, ...)
 # BMultipoleParams bookkeeping.
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{BMultipoleParams}, changed::ChangedLedger, previous_ele::Ele)
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{BMultipoleParams}, changed::ChangedLedger, previous_ele::Ele)
   bmg = ele.BMultipoleParams
   cdict = ele.changed
   if !has_changed(ele, BMultipoleParams) && !changed.this_ele_length && !changed.reference; return; end
@@ -454,10 +454,10 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{BMultipoleParams}, changed::
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{BendParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{BendParams}, ...)
 # BendParams bookkeeping.
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{BendParams}, changed::ChangedLedger, previous_ele::Ele)
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{BendParams}, changed::ChangedLedger, previous_ele::Ele)
   bg = ele.BendParams
   cdict = ele.changed
 
@@ -523,7 +523,7 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{BendParams}, changed::Change
 
     if ele.L != L
       ele.L = L
-      elegroup_bookkeeper!(ele, LengthParams, changed, previous_ele)
+      ele_paramgroup_bookkeeper!(ele, LengthParams, changed, previous_ele)
     end
 
     if haskey(cdict, :e1)
@@ -553,10 +553,10 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{BendParams}, changed::Change
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{LengthParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{LengthParams}, ...)
 # Low level LengthParams bookkeeping.
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{LengthParams}, changed::ChangedLedger, previous_ele::Ele)
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{LengthParams}, changed::ChangedLedger, previous_ele::Ele)
   lg = ele.LengthParams
   cdict = ele.changed
 
@@ -585,15 +585,15 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{LengthParams}, changed::Chan
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{RFParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{RFParams}, ...)
 
 """
-    elegroup_bookkeeper!(ele::Ele, group::Type{RFParams}, changed::ChangedLedger, previous_ele::Ele)
+    ele_paramgroup_bookkeeper!(ele::Ele, group::Type{RFParams}, changed::ChangedLedger, previous_ele::Ele)
 
 `RFParams` bookkeeping.
 """
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{RFParams}, changed::ChangedLedger, previous_ele::Ele)
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{RFParams}, changed::ChangedLedger, previous_ele::Ele)
   rg = ele.RFParams
   cdict = ele.changed
 
@@ -620,15 +620,15 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{RFParams}, changed::ChangedL
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{ReferenceParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{ReferenceParams}, ...)
 
 """
-    elegroup_bookkeeper!(ele::Ele, group::Type{ReferenceParams}, changed::ChangedLedger, previous_ele::Ele)
+    ele_paramgroup_bookkeeper!(ele::Ele, group::Type{ReferenceParams}, changed::ChangedLedger, previous_ele::Ele)
 
 `ReferenceParams` bookkeeping. This also includes `DownstreamReferenceParams` bookkeeping.
 """
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{ReferenceParams}, changed::ChangedLedger, previous_ele::Ele)
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{ReferenceParams}, changed::ChangedLedger, previous_ele::Ele)
   rg = ele.ReferenceParams
   drg = ele.DownstreamReferenceParams
   cdict = ele.changed
@@ -716,10 +716,10 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{ReferenceParams}, changed::C
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{FloorParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{FloorParams}, ...)
 # FloorParams bookkeeper
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{FloorParams}, 
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{FloorParams}, 
                                               changed::ChangedLedger, previous_ele::Ele)
   fpg = ele.FloorParams
   cdict = ele.changed
@@ -736,10 +736,29 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{FloorParams},
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{SolenoidParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{ForkParams}, ...)
+# ForkParams bookkeeper
+
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{ForkParams}, 
+                                              changed::ChangedLedger, previous_ele::Ele)
+
+  fg = ele.ForkParams
+
+
+
+  if to_ele.species_ref == Species("Null"); to_ele.species_ref = fork.species_ref; end
+  if to_ele.pc_ref == NaN && to_ele.E_tot_ref == NaN
+    to_ele.pc_ref = fork.pc_ref
+    to_ele.E_tot_ref = fork.pc_ref
+  end
+
+end
+
+#---------------------------------------------------------------------------------------------------
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{SolenoidParams}, ...)
 # SolenoidParams bookkeeping.
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{SolenoidParams}, changed::ChangedLedger, previous_ele::Ele)
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{SolenoidParams}, changed::ChangedLedger, previous_ele::Ele)
   sg = ele.SolenoidParams
   cdict = ele.changed
   if !has_changed(ele, SolenoidParams) && !changed.reference; return; end
@@ -761,10 +780,10 @@ function elegroup_bookkeeper!(ele::Ele, group::Type{SolenoidParams}, changed::Ch
 end
 
 #---------------------------------------------------------------------------------------------------
-# elegroup_bookkeeper!(ele::Ele, group::Type{TrackingParams}, ...)
+# ele_paramgroup_bookkeeper!(ele::Ele, group::Type{TrackingParams}, ...)
 # Low level LengthParams bookkeeping.
 
-function elegroup_bookkeeper!(ele::Ele, group::Type{TrackingParams}, changed::ChangedLedger, previous_ele::Ele)
+function ele_paramgroup_bookkeeper!(ele::Ele, group::Type{TrackingParams}, changed::ChangedLedger, previous_ele::Ele)
   tg = ele.TrackingParams
   cdict = ele.changed
 
@@ -939,22 +958,24 @@ function fork_bookkeeper(fork::Ele)
 
   # Fork to new branch
   else
+    lat = fork.branch.lat
     to_branch = new_tracking_branch!(lat, fork.to_line)
     if typeof(fork.to_ele) == Ele; error(
       "Since to_line is specified, to_ele must be something (String, Regex) that can be used with \n" *
       "the `find` function to locate the element in the new branch and cannot be an existing element."); end
-    to_ele = find(fork.to_ele)
-    if length(to_ele) == 0; error("to_ele ($(fork.to_ele)) not found in new branch for fork $(fork.name)."); end
-    if length(to_ele) > 1; error("Multiple elements matched to to_ele ($(fork.to_ele)) for fork $(fork.name)."); end
-    fork.to_ele = to_ele[1]
+
+    if fork.to_ele == ""
+      fork.to_ele = to_branch[1]
+    else
+      to_ele = eles(fork.to_ele)
+      if length(to_ele) == 0; error("to_ele ($(fork.to_ele)) not found in new branch for fork $(fork.name)."); end
+      if length(to_ele) > 1; error("Multiple elements matched to to_ele ($(fork.to_ele)) for fork $(fork.name)."); end
+      fork.to_ele = to_ele[1]
+    end
 
     to_ele = fork.to_ele
     if to_ele.ix_ele == 1
-      if to_ele.species_ref == Species("Null"); to_ele.species_ref = fork.species_ref; end
-      if to_ele.pc_ref == NaN && to_ele.E_tot_ref == NaN
-        to_ele.pc_ref = fork.pc_ref
-        to_ele.E_tot_ref = fork.pc_ref
-      end
+      to_ele.from_forks = [fork]
     end
   end
 
diff --git a/src/geometry.jl b/src/geometry.jl
index 6e9a530..4a40d65 100644
--- a/src/geometry.jl
+++ b/src/geometry.jl
@@ -66,7 +66,7 @@ function coord_transform(ds::Number, g::Number, tilt_ref::Number = 0.0)
 
   else
     angle = ds/g
-    r_vec = ds * [-angle * un_cosc(angle), 0.0, un_sinc(angle)]
+    r_vec = ds * [-angle * coscu(angle), 0.0, sincu(angle)]
 
     qa = rotY(-angle)
     if tilt_ref == 0
diff --git a/src/show.jl b/src/show.jl
index 3a1697b..9dfd075 100644
--- a/src/show.jl
+++ b/src/show.jl
@@ -153,7 +153,7 @@ List of parameters not to show when displaying the parameters of an element, bra
 These parameters are redundant and are not shown to save space.
 """ DO_NOT_SHOW_PARAMS_LIST
 
-DO_NOT_SHOW_PARAMS_LIST = Vector{Symbol}([:q_body, :q_body_tot, 
+DO_NOT_SHOW_PARAMS_LIST = Vector{Symbol}([:q_body, :q_body_tot, :to_line,
                 :x_rot_floor, :y_rot_floor, :z_rot_floor, :drift_master])
 
 #---------------------------------------------------------------------------------------------------
@@ -590,12 +590,14 @@ function Base.show(io::IO, branch::Branch)
         s_str = ele_param_value_str(ele, :s, default = "    "*"-"^7, format = "12.6f")
         s_down_str = ele_param_value_str(ele, :s_downstream, default = "    "*"-"^7, format = "12.6f")
         end_str = f"{ele.L:12.6f}{s_str} ->{s_down_str}"
-        if haskey(ele.pdict, :multipass_lord); end_str = end_str * f"  {ele_param_value_str(ele.pdict, :multipass_lord, default = \"\")}"; end
-        if haskey(ele.pdict, :super_lords);  end_str = end_str * f"  {ele_param_value_str(ele.pdict, :super_lords, default = \"\")}"; end
-        if haskey(ele.pdict, :slaves); end_str = end_str * f"  {ele_param_value_str(ele.pdict, :slaves, default = \"\")}"; end
-        if ele.orientation == -1; end_str = end_str * "  orientation = -1"; end
+        if haskey(ele.pdict, :multipass_lord); end_str *= "  $(ele_param_value_str(ele.pdict, :multipass_lord, default = ""))"; end
+        if haskey(ele.pdict, :super_lords);    end_str *= "  $(ele_param_value_str(ele.pdict, :super_lords, default = ""))"; end
+        if haskey(ele.pdict, :slaves);         end_str *= "  $(ele_param_value_str(ele.pdict, :slaves, default = ""))"; end
+        if haskey(ele.pdict, :ForkParams);     end_str *= "  Fork to: $(ele_param_value_str(ele.to_ele, default = "???"))"; end
+        if haskey(ele.pdict, :from_forks);     end_str *= "  From fork: $(ele_param_value_str(ele.from_forks, default = "???"))"; end
+        if ele.orientation == -1; end_str *= "  orientation = -1"; end
       end
-      println(io, f"  {ele.pdict[:ix_ele]:5i}  {rpad(str_quote(ele.name), n)} {rpad(typeof(ele), 16)}" * end_str)                    
+      println(io, "  $(lpad(ele.pdict[:ix_ele], 5))  $(rpad(str_quote(ele.name), n)) $(rpad(typeof(ele), 16))" * end_str)                    
     end
   end
   return nothing
diff --git a/src/struct.jl b/src/struct.jl
index 8a1a112..8481ea3 100644
--- a/src/struct.jl
+++ b/src/struct.jl
@@ -740,13 +740,13 @@ Fork element parameters.
 
 ## Fields
 • `to_line::Union{BeamLine,Nothing}`  - Beam line to fork to. \\
-• `to_ele`                            - On input: Element ID or element itself. \\
+• `to_ele::Union{String,Ele}`         - On input: Element ID or element itself. \\
 • `direction::Int`                    - Longitudinal Direction of injected beam. \\
 """ ForkParams
 
 @kwdef mutable struct ForkParams <: EleParams
   to_line::Union{BeamLine,Nothing} = nothing
-  to_ele::Union = ""
+  to_ele::Union{String,Ele} = ""
   direction::Int = +1
 end
 
@@ -1115,9 +1115,9 @@ Lattice branch structure.
 
 ## Fields
 • `name::String`                      - Name of the branch. \\
-• `lat::Union{AbstractLattice, Nothing}`  - Pointer to the lattice containing the branch. \\
 • `ele::Vector{Ele}`                  - Pointer to the array of lattice element contained in the branch. \\
 • `pdict::Dict{Symbol,Any}`           - Dict for holding other branch parameters. \\
+• `lat::Union{AbstractLattice, Nothing}`  - Pointer to the lattice containing the branch. \\
 
 Note: `AbstractLattice` is used here since `Lattice` is not yet defined and Julia does not allow forward 
 struct declarations.
diff --git a/src/utilities.jl b/src/utilities.jl
index 0c81dc6..c30ef3b 100644
--- a/src/utilities.jl
+++ b/src/utilities.jl
@@ -32,11 +32,11 @@ function lat_sanity_check(lat::Lattice)
                                       " element index: $ie has ele.ix_ele set to $(ele.ix_ele)"); end
 
       if !(branch === ele.branch)
-        error("SanityCheck: Ele $(ele_name(ele)) has ele.branch not pointing to parient branch.")
+        error("Ele $(ele_name(ele)) has ele.branch not pointing to parient branch.")
       end
 
       if branch.type == TrackingBranch && !haskey(pdict, :LengthParams)
-        error("Sanity check: Ele $(ele_name(ele)) does not have a LengthParams group.")
+        error("Ele $(ele_name(ele)) does not have a LengthParams group.")
       end
       
       if haskey(pdict, :girder)
@@ -49,6 +49,7 @@ function lat_sanity_check(lat::Lattice)
 
       if haskey(pdict, :ForkParams)
         lat_sanity_check(lat, ele, pdict[:ForkParams].to_ele, "a forked-to element")
+        if ele.L != 0; error("A Fork element may not have a non-zero length: $(ele_name(ele))"); end
       end
 
       if haskey(pdict, :OriginEleParams)
@@ -78,7 +79,7 @@ function lat_sanity_check(lat::Lattice)
           lat_sanity_check(lat, ele, slave, "supported element")
         end
       end
-      
+
     end
   end
 end
diff --git a/test/fork_test.jl b/test/fork_test.jl
new file mode 100644
index 0000000..7a3efcb
--- /dev/null
+++ b/test/fork_test.jl
@@ -0,0 +1,32 @@
+using AcceleratorLattice, Test
+
+@ele begin1 = BeginningEle(species_ref = Species("electron"), pc_ref = 1e6)
+@ele begin2 = BeginningEle()
+
+@ele bend1 = Bend(g = 1, angle = pi/2, Kn2L = 0.1, Bs3 = 0.2, En4 = 0.3, Es5L = 0.4)
+bend2 = copy(bend1)
+bend2.name = "bend2"
+bend2.tilt_ref = pi/2
+
+@ele fork1 = Fork()
+
+line1 = BeamLine([begin1, bend1, fork1])
+line2 = BeamLine([begin2, bend2])
+fork1.to_line = line2
+
+lat = Lattice([line1])
+
+b1 = lat.branch[1]
+b2 = lat.branch[2]
+
+@testset "bend_bookkeeping" begin
+
+
+end
+
+# test fork superimpose
+# test fork to existing branch.
+# make sure finite L throws error.
+# check that forked to branch inherits reference energy from fork.
+# Restriction? If forking to a new branch, must fork to beginning of branch.
+# Check that changes in reference or floor at fork gets propagated to to-branch.
\ No newline at end of file
diff --git a/test/runtests.jl b/test/runtests.jl
index f6083fe..4f7137d 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -14,6 +14,10 @@ using AcceleratorLattice, Test
     include("find_test.jl")
   end
 
+#  @testset "fork_test" begin
+#    include("fork_test.jl")
+#  end
+
   @testset "string_test" begin
     include("string_test.jl")
   end